(This file was generated from ../fetchmail-FAQ.html)
_________________________________________________________________
Frequently Asked Questions About Fetchmail
Before reporting any bug, please read G3 for advice on how to include
diagnostic information that will get your bug fixed as quickly as possible.
Note that this FAQ is occasionally updated from the SVN repository and
speaks in the past tense ("since") about a fetchmail release that is not yet
available. Please try a release candidate for that version in case you need
the new option.
If you have a question or answer you think ought to be added to this FAQ
list, file it to one of the trackers at our BerliOS project site or post to
one of the fetchmail mailing lists (see below).
Contents
Detailed Contents
G. General problems
B. Build-time problems
F. Fetchmail configuration file grammar questions
C. Configuration questions
T. How to make fetchmail play nice with various MTAs
S. How to make fetchmail work with various servers
I. How to fetchmail work with specific ISPs
K. How to set up well-known security and authentication
R. Runtime fatal errors
H. Hangs and lockups
D. Disappearing mail
M. Multidrop-mode problems
X. Mangled mail
O. Other problems
Detailed Contents
General problems
G1. What is fetchmail and why should I bother?
G2. Where do I find the latest FAQ and fetchmail sources?
G3. I think I've found a bug. Will you fix it?
G4. I have this idea for a neat feature. Will you add it?
G5. I want to make fetchmail behave like Outlook Express.
G6. Is there a mailing list for exchanging tips?
G7. So, what's this I hear about a fetchmail paper?
G8. What is the best server to use with fetchmail?
G9. What is the best mail program to use with fetchmail?
G10. How can I avoid sending my password en clair?
G11. Is any special configuration needed to use a dynamic IP address?
G12. Is any special configuration needed to use firewalls?
G13. Is any special configuration needed to send mail?
G14. Is fetchmail Y2K-compliant?
G15. Is there a way in fetchmail to support disconnected IMAP mode?
G16. How will fetchmail perform under heavy loads?
Build-time problems
[DEL: B1. Make coughs and dies when building on FreeBSD. :DEL]
B2. Lex bombs out while building the fetchmail lexer.
B3. I get link failures when I try to build fetchmail.
B4. I get build failures in the intl directory.
Fetchmail configuration file grammar questions
F1. Why does my old .fetchmailrc no longer work?
F2. The .fetchmailrc parser won't accept my all-numeric user name.
F3. The .fetchmailrc parser won't accept my host or username beginning with
'no'.
F4. I'm getting a 'parse error' message I don't understand.
Configuration questions
C1. Why do I need a .fetchmailrc when running as root on my own machine?
C2. How can I arrange for a fetchmail daemon to get killed when I log out?
C3. How do I know what interface and address to use with --interface?
C4. How can I set up support for sendmail's anti-spam features?
C5. How can I poll some of my mailboxes more/less often than others?
C6. Fetchmail works OK started up manually, but not from an init script.
C7. How can I forward mail to another host?.
How to make fetchmail play nice with various MTAs
T1. How can I use fetchmail with sendmail?
T2. How can I use fetchmail with qmail?
T3. How can I use fetchmail with exim?
T4. How can I use fetchmail with smail?
T5. How can I use fetchmail with SCO's MMDF?
T6. How can I use fetchmail with Lotus Notes?
T7. How can I use fetchmail with Courier IMAP?
T8. How can I use fetchmail with vbmailshield?
How to make fetchmail work with various servers
S1. How can I use fetchmail with qpopper?
S2. How can I use fetchmail with Microsoft Exchange?
S3. How can I use fetchmail with HP OpenMail?
S4. How can I use fetchmail with Novell GroupWise?
S5. How can I use fetchmail with InterChange?
S6. How can I use fetchmail with MailMax?
S7. How can I use fetchmail with FTGate?
How to fetchmail work with specific ISPs
I1. How can I use fetchmail with Compuserve RPA?
I2. How can I use fetchmail with Demon Internet's SDPS?
I3. How can I use fetchmail with usa.net's servers?
I4. How can I use fetchmail with geocities POP3 servers?
I5. How can I use fetchmail with Hotmail or Lycos Webmail?
I6. How can I use fetchmail with MSN?
I7. How can I use fetchmail with SpryNet?
I8. How can I use fetchmail with comcast.net or other Maillennium servers?
How to set up well-known security and authentication methods
K1. How can I use fetchmail with SOCKS?
K2. How can I use fetchmail with IPv6 and IPsec?
K3. How can I get fetchmail to work with ssh?
K4. What do I have to do to use the IMAP-GSS protocol?
K5. How can I use fetchmail with SSL?
K6. How can I tell fetchmail not to try TLS if the server advertises it?
Runtime fatal errors
R1. Fetchmail isn't working, and -v shows 'SMTP connect failed' messages.
R2. When I try to configure an MDA, fetchmail doesn't work.
R3. Fetchmail dumps core when given an invalid rc file.
R4. Fetchmail dumps core in -V mode, but operates normally otherwise.
R5. Running fetchmail in daemon mode doesn't work.
R6. Fetchmail randomly dies with socket errors.
R7. Fetchmail running as root stopped working after an OS upgrade
R8. Fetchmail is timing out after fetching certain messages but before
deleting them
R9. Fetchmail is timing out during message fetches
R10. Fetchmail is dying with SIGPIPE.
R11. My server is hanging or emitting errors on CAPA.
R12. Fetchmail isn't working and reports getaddrinfo errors.
Hangs and lockups
H1. Fetchmail hangs when used with pppd.
H2. Fetchmail hangs during the MAIL FROM exchange.
H3. Fetchmail hangs while fetching mail.
Disappearing mail
D1. I think I've set up fetchmail correctly, but I'm not getting any mail.
D2. All my mail seems to disappear after a dropped connection.
D3. Mail that was being fetched when I interrupted my fetchmail seems to
have been vanished.
Multidrop-mode problems
M1. I've declared local names, but all my multidrop mail is going to root
anyway.
M2. I can't seem to get fetchmail to route to a local domain properly.
M3. I tried to run a mailing list using multidrop, and I have a mail loop!
M4. My multidrop fetchmail seems to be having DNS problems.
M5. I'm seeing long DNS delays before each message is processed.
M6. How do I get multidrop mode to work with majordomo?
M7. Multidrop mode isn't parsing envelope addresses from my Received headers
as it should.
M8. Users are getting multiple copies of messages.
Mangled mail
X1. Spurious blank lines are appearing in the headers of fetched mail.
X2. My mail client can't see a Subject line.
X3. Messages containing "From" at start of line are being split.
X4. My mail is being mangled in a new and different way.
X5. Using POP3, retrievals seems to be fetching too much!
X6. My mail attachments are being dropped or mangled.
X7. Some mail attachments are hanging fetchmail.
X8. A spurious ) is being appended to my messages.
X9. Missing "Content-Transfer-Encoding" header with Domino IMAP
Other problems
O1. The --logfile option doesn't work if the logfile doesn't exist.
O2. Every time I get a POP or IMAP message the header is dumped to all my
terminal sessions.
O3. Does fetchmail reread its rc file every poll cycle?
O4. Why do deleted messages show up again when I take a line hit while
downloading?
O5. Why is fetched mail being logged with my name, not the real From
address?
O6. I'm seeing long sendmail delays or hangs near the start of each poll
cycle.
O7. Why doesn't fetchmail deliver mail in date-sorted order?
O8. I'm using pppd. Why isn't my monitor option working?
O9. Why does fetchmail keep retrieving the same messages over and over?
O10. Why is the received date on all my messages the same?
O11. I keep getting messages that say "Repoll immediately" in my logs.
O12. Fetchmail no longer expunges mail on a 451 SMTP response.
O13. I want timestamp information in my fetchmail logs.
O14. Fetchmail no longer deletes oversized mails with --flush.
O15. Fetchmail always retains the first message in the mailbox.
O16. Why is the Fetchmail FAQ only available in ISO-216 A4 format? How do I
get the FAQ in Letter format?
_________________________________________________________________
General problems
G1. What is fetchmail and why should I bother?
Fetchmail is a one-stop solution to the remote mail retrieval problem for
Unix machines, quite useful to anyone with an intermittent PPP or SLIP
connection to a remote mailserver. It can collect mail using any variant of
POP or IMAP and forwards via port 25 to the local SMTP listener, enabling
all the normal forwarding/filtering/aliasing mechanisms that would apply to
local mail or mail arriving via a full-time TCP/IP connection.
Fetchmail is not a toy or a coder's learning exercise, but an
industrial-strength tool capable of transparently handling every retrieval
demand from those of a simple single-user ISP connection up to mail
retrieval and rerouting for an entire client domain. Fetchmail is easy to
configure, unobtrusive in operation, powerful, feature-rich, and well
documented.
Fetchmail is open-source software. The openness of the sources is the
strongest assurance of quality you can have. Extensive peer review by a
large, multi-platform user community has shown that fetchmail is as near
bulletproof as the underlying protocols permit.
Fetchmail is licensed under the GNU General Public License.
If you found this FAQ in the distribution, see the README for fetchmail's
full feature list.
G2. Where do I find the latest FAQ and fetchmail sources?
The latest HTML FAQ is available alongside the latest fetchmail sources at
the fetchmail home page: http://fetchmail.berlios.de/. You can also usually
find both in the POP mail tools directory on iBiblio.
A text dump of this FAQ is included in the fetchmail distribution. Because
it freezes at distribution release time, it may not be completely current.
G3. I think I've found a bug. Will you fix it?
The first thing you should to is to upgrade to the newest version of
fetchmail, and then see if the problem reproduces. So you'll probably save
us both time if you upgrade and test with the latest version before sending
in a bug report.
I will fix bugs, provided you include enough diagnostic information for me
to go on. Send bugs to fetchmail-users. When reporting bugs, please include
the following:
1. Your operating system.
2. Your compiler version, if you built from source; otherwise, the name and
origin of the RPM or other binary package you installed.
3. A copy of your POP or IMAP server's greeting line.
4. The name and version of the SMTP listener or MDA you are forwarding to.
5. Any command-line options you used.
6. The output of fetchmail -V called with whatever other command-line
options you used.
If you have FTP access to your remote mail account, and you have any
suspicion that the bug was triggered by a particular message, please include
a copy of the message that triggered the bug.
If your bug is something that used to work but stopped working when you
upgraded, then you can help pin the bug down by trying intermediate versions
of fetchmail until you identify the revision that broke your feature. The
smart way to do this is by binary search on the version sequence. First, try
the version halfway between your last good one and the current one. If it
works, the failure was introduced in the upper half of the sequence; if it
doesn't, the failure was introduced in the lower half. Now bisect that half
in the same way. In a very few tries, you should be able to identify the
exact adjacent pair of versions between which your bug was introduced -- and
with information like that, I can usually come up with a fix very quickly.
Another useful thing you can do, if you're using POP3, is to test for IMAP4
support on your mailserver using the autoprobe function of fetchmailconf. If
you have IMAP4, and fetchmailconf doesn't tell you it's broken, switch
immediately. POP3 is a weak, poorly-designed protocol with chronic problems,
and the later versions after RFC1725 actually get worse rather than better.
Changing over to IMAP4 may well make your problem go away -- and if your ISP
doesn't have IMAP4 support, bug them to supply it.
It is helpful if you include your .fetchmailrc file, but not necessary
unless your symptom seems to involve an error in configuration parsing. If
you do send in your .fetchmailrc, mask the passwords first!
If fetchmail seems to run and fetch mail, but the headers look mangled (that
is, headers are missing or blank lines are inserted in the headers) then
read the FAQ items in section X before submitting a bug report. Pay special
attention to the item on diagnosing mail mangling. There are lots of ways
for other programs in the mail chain to screw up that look like fetchmail's
fault, but you may be able to fix these by tweaking your configuration.
A transcript of the failed session with -v -v (yes, that's two -v options,
enabling debug mode) will almost always be useful. It is very important that
the transcript include your POP/IMAP server's greeting line, so I can
identify it in case of server problems. This transcript will not reveal your
passwords, which are specially masked out precisely so transcripts can be
passed around.
If you upgraded your fetchmail and something broke, you should include
session transcripts with -v -v of both the working and failing versions.
Very often, the source of the problem can instantly identified by looking at
the differences in protocol transactions.
If the bug involves a core dump or hang, a gdb stack trace is good to have.
(Bear in mind that you can attach gdb to a running but hung process by
giving the process ID as a second argument.) You will need to reconfigure
with:
CFLAGS=-g LDFLAGS=" " ./configure
Then rebuild in order to generate a version that can be gdb-traced.
Best of all is a mail file which, when fetched, will reproduce the bug under
the latest (current) version.
Any bug I can reproduce will usually get fixed very quickly, often within 48
hours. Bugs I can't reproduce are a crapshoot. If the solution isn't obvious
when I first look, it may evade me for a long time (or to put it another
way, fetchmail is well enough tested that the easy bugs have long since been
found). So if you want your bug fixed rapidly, it is not just sufficient but
nearly necessary that you give me a way to reproduce it.
G4. I have this idea for a neat feature. Will you add it?
If it's reasonable for fetchmail and cannot be solved with reasonable effort
outside of fetchmail, perhaps.
You can do spam filtering better with procmail or maildrop on the server
side and (if you're the server sysadmin) sendmail.cf domain exclusions. If
you really want fetchmail to do it from the client side, use a preconnect
command to call mailfilter.
You can do other policy things better with the mda option and script
wrappers around fetchmail. If it's a prime-time-vs.-non-prime-time issue,
ask yourself whether a wrapper script called from crontab would do the job.
fetchmail's first job is transport though, and it should do this well. If a
feature would cause fetchmail to deteriorate in other respects, the feature
will probably not be added.
For reasons fetchmail doesn't have other commonly-requested features (such
as password encryption, or multiple concurrent polls from the same instance
of fetchmail) see ESR's design notes. Note that this document is partially
obsoleted by the updated design notes.
G5. I want to make fetchmail behave like Outlook Express.
The second-most-requested feature for fetchmail, after content-based
filtering, is the ability to have it remove messages from a maildrop after N
days, typically to be used with the keep option as a sort of poor man's
newsgroup facility. Microsoft's Outlook Express supports this.
This feature is not yet implemented. It may be at a future date, spare time
of developers permitting.
G6. Is there a mailing list for exchanging tips?
There is a fetchmail-users list (fetchmail-users@lists.berlios.de) for bug
reports and people who want to discuss configuration issues of fetchmail.
It's a Mailman list, see
http://lists.berlios.de/mailman/listinfo/fetchmail-users.
There is a fetchmail-devel list (fetchmail-devel@lists.berlios.de) for
people who want to discuss fixes and improvements in fetchmail and help
co-develop it. It's a Mailman list, which you can sign up for at
http://lists.berlios.de/mailman/listinfo/fetchmail-devel. There is also an
announcements-only list, fetchmail-announce@lists.berlios.de, which you can
sign up for at http://lists.berlios.de/mailman/listinfo/fetchmail-announce.
G7. So, what's this I hear about a fetchmail paper?
The fetchmail development was also a sociological experiment, an extended
test to see if my theory about the critical features of the Linux
development model is correct.
The experiment was a success. I wrote a paper about it titled The Cathedral
and the Bazaar which was first presented at Linux Kongress '97 in Bavaria
and very well received there. It was also given at Atlanta Linux Expo, Linux
Pro '97 in Warsaw, and the first Perl Conference, at UniForum '98, and was
the basis of an invited presentation at Usenix '98. The folks at Netscape
tell me it helped them decide to give away the source for Netscape
Communicator.
If you're reading a non-HTML dump of this FAQ, you can find the paper on the
Web with a search for that title.
G8. What is the best server to use with fetchmail?
Fetchmail will work with any POP, IMAP, ETRN, or ODMR server that conforms
to the relevant RFCs (and even some outright broken ones like Microsoft
Exchange and Novell GroupWise). This doesn't mean it works equally well with
all, however. POP2 servers, and POP3 servers without UIDL, limit fetchmail's
capabilities in various ways described on the manual page.
Most modern Unixes (and effectively all Linux/*BSD systems) come with POP3
support preconfigured (but beware of the horribly broken POP3 server
mentioned in D2). An increasing minority also feature IMAP (you can detect
IMAP support by running fetchmail in AUTO mode, or by using the 'Probe for
supported protocols' function in the fetchmailconf utility).
If you have the option, we recommend using or installing an IMAP4rev1
server; it has the best facilities for tracking message 'seen' states. It
also recovers from interrupted connections more gracefully than POP3, and
enables some significant performance optimizations.
Don't be fooled by NT/Exchange propaganda. M$ Exchange is just plain broken
(see item S2) and NT cannot handle the sustained load of a high-volume
remote mail server. Even Microsoft itself knows better than to try this;
their own Hotmail service runs over Solaris! For extended discussion, see
John Kirch's excellent white paper on Unix vs. NT performance.
A decent POP3/IMAP server that has recently become popular is Dovecot.
Avoid qmail, it's broken.
G9. What is the best mail program to use with fetchmail?
Fetchmail will work with all popular mail transport programs. It also
doesn't care which user agent you use, and user agents are as a rule almost
equally indifferent to how mail is delivered into your system mailbox. So
any of the popular Unix mail agents -- elm, pine, mh, or mutt -- will work
fine with fetchmail.
All this having been said, I can't resist putting in a discreet plug for
mutt. Mutt's interface is only a little different from that of its
now-moribund ancestor elm, but its flexibility and excellent handling of
MIME and PGP put it in a class by itself. You won't need its built-in POP3
support, though; most of the mutt developers will cheerfully admit that
fetchmail's is better :-).
G10. How can I avoid sending my password en clair?
Depending on what your mail server you are talking to, this ranges from
trivial to impossible. It may even be next to useless.
Most people use fetchmail over phone wires (whether plain old copper or
DSL), which are hard to tap. Anybody with the skill and resources to do this
could get into your server mailbox with much less effort by subverting the
server host. So if your provider setup is phone-company wire going straight
into a service box, you probably don't need to worry.
In general there is little point in trying to secure your fetchmail
transaction unless you trust the security of the server host you are
retrieving mail from. Your vulnerability is more likely to be an insecure
local network on the server end (e.g. to somebody with a TCP/IP packet
sniffer intercepting Ethernet traffic between the modem concentrator or DSL
POP you dial in to and the mailserver host).
Having realized this, you need to ask whether password encryption alone will
really address your security exposure. If you think you might be snooped
between server and client, it's better to use end-to-end encryption on your
whole mail stream so none of it can be read. One of the advantages of
fetchmail over conventional SMTP-push delivery is that you may be able to
arrange this by using ssh(1); see K3.
Note that ssh is not a complete privacy solution either, as your mail could
have been snooped in transit to your POP server from wherever it originated.
For best security, agree with your correspondents to use a tool such as GPG
(Gnu Privacy Guard) or PGP (Pretty Good Privacy).
If ssh/sshd isn't available, or you find it too complicated for you to set
up, password encryption will at least keep a malicious cracker from deleting
your mail, and require him to either tap your connection continuously or
crack root on the server in order to read it.
You can deduce what encryptions your mail server has available by looking at
the server greeting line (and, for IMAP, the response to a CAPABILITY
query). Do a fetchmail -v to see these, or telnet direct to the server port
(110 for POP3, 143 for IMAP).
If your mailserver is using IMAP 2000, you'll have CRAM-MD5 support built
in. Fetchmail autodetects this; you can skip the rest of this section.
The POP3 facility you are most likely to have available is APOP. This is a
POP3 feature supported by many servers (fetchmailconf's autoprobe facility
will detect it and tell you if you have it). If you see something in the
greeting line that looks like an angle-bracket-enclosed Internet address
with a numeric left-hand part, that's an APOP challenge (it will vary each
time you log in). You can register a secret on the host (using popauth(8) or
some program like it). Specify the secret as your password in your
.fetchmailrc; it will be used to encrypt the current challenge, and the
encrypted form will be sent back the the server for verification.
Alternatively, you may have Kerberos available. This may require you to set
up some magic files in your home directory on your client machine, but means
you can omit specifying any password at all.
Fetchmail supports two different Kerberos schemes. One is a POP3 variant
called KPOP; consult the documentation of your mail server to see if you
have it (one clue is the string "krb-IV" in the greeting line on port 110).
The other is an IMAP and POP3 facility described by RFC1731 and RFC1734. You
can tell if this one is present by looking for AUTH=KERBEROS_V4 in the
CAPABILITY response.
If you are fetching mail from a CompuServe POP3 account, you can use their
RPA authentication (which works much like APOP). See I1 for details. If you
are fetching mail from Microsoft Exchange using IMAP, you will be able to
use NTLM.
Your POP3 server may have the RFC1938 OTP capability to use one-time
passwords (if it doesn't, you can get OTP patches for the 2.2 version of the
Qualcomm popper from Craig Metz). To check this, look for the string "otp-"
in the greeting line. If you see it, and your fetchmail was built with OPIE
support compiled in (see the distribution INSTALL file), fetchmail will
detect it also. When using OTP, you will specify a password but it will not
be sent en clair.
You can get both POP3 and IMAP OTP patches from Craig Metz at
http://www.inner.net/opie.
These patches use a SASL authentication method named "X-OTP" because there
is not currently a standard way to do this; fetchmail also uses this method,
so the two will interoperate happily. They better, because this is how Craig
gets his mail ;-)
Finally, you can use SSL for complete end-to-end encryption if you have an
SSL-enabled mailserver.
G11. Is any special configuration needed to use a dynamic IP address?
Yes. In order to avoid giving indigestion to certain picky MTAs (notably
exim), fetchmail always makes the RCPT TO address it feeds the MTA a fully
qualified one with a hostname part. Normally it does this by appending @ and
"localhost", but when you are using Kerberos or ETRN mode it will append @
and your machine's fully-qualified domain name (FQDN).
Appending the FQDN can create problems when fetchmail is running in daemon
mode and outlasts the dynamic IP address assignment your client machine had
when it started up.
Since the new IP address (looked up at RCPT TO interpretation time) doesn't
match the original, the most benign possible result is that your MTA thinks
it's seeing a relaying attempt and refuses. More frequently, fetchmail will
try to connect to a nonexistent host address and time out. Worst case, you
could up forwarding your mail to the wrong machine!
Use the smtpaddress option to force the appended hostname to one with a
(fixed) IP address of 127.0.0.1 in your /etc/hosts. (The name 'localhost'
will usually work; or you can use the IP address itself).
Only one fetchmail option interacts directly with your IP address,
'interface'. This option can be used to set the gateway device and restrict
the IP address range fetchmail will use. Such a restriction is sometimes
useful for security reasons, especially on multihomed sites. See C3.
I recommend against trying to set up the interface option when initially
developing your poll configuration -- it's never necessary to do this just
to get a link working. Get the link working first, observe the actual
address range you see on connections, and add an interface option (if you
need one) later.
You can't use ETRN if you have a dynamic IP address (your ISP changes your
IP address occasionally, possibly with every connect). You need to have your
own registered domain and a definite IP address registered for that domain.
The server needs to be configured to accept mail for your domain but then
queue it to forward to your machine. ETRN just tells to server to flush its
queue for your domain. Fetchmail doesn't actually get the mail in that case.
You can use On-Demand Mail Relay (ODMR) with a dynamic IP address; that's
what it was designed for, and it provides capabilities very similar to ETRN.
Unfortunately ODMR servers are not yet widely deployed, as of early 2001.
If you're using a dynamic-IP configuration, one other (non-fetchmail)
problem you may run into with outgoing mail is that some sites will bounce
your email because the hostname your giving them isn't real (and doesn't
match what they get doing a reverse DNS on your dynamically-assigned IP
address). If this happens, you need to hack your sendmail so it masquerades
as your host. Setting
DMsmarthost.here
in your sendmail.cf will work, or you can set
MASQUERADE_AS(smarthost.here)
in the m4 configuration and do a reconfigure. (In both cases, replace
smarthost.here with the actual name of your mailhost.) See the sendmail FAQ
for more details.
G12. Is any special configuration needed to use firewalls?
No. You can use fetchmail with SOCKS, the standard tool for indirecting
TCP/IP through a firewall. You can find out about SOCKS, and download the
SOCKS software including server and client code, at the SOCKS distribution
site.
The specific recipe for using fetchmail with a firewall is at K1
G13. Is any special configuration needed to send mail?
A user asks: but how do we send mail out to the POP3 server? Do I need to
implement another tool or will fetchmail do this too?
Fetchmail only handles the receiving side. The sendmail or other
preinstalled MTA on your client machine will handle sending mail
automatically; it will ship mail that is submitted while the connection is
active, and put mail that is submitted while the connection is inactive into
the outgoing queue.
Normally, sendmail is also run periodically (every 15 minutes on most Linux
systems) in a mode that tries to ship all the mail in the outgoing queue. If
you have set up something like pppd to automatically dial out when your
kernel is called to open a TCP/IP connection, this will ensure that the mail
gets out.
G14. Is fetchmail Y2K-compliant?
Fetchmail is fully Y2K-compliant.
Fetchmail could theoretically have problems when the 32-bit time_t counters
roll over in 2038, but I doubt it. Timestamps aren't used for anything but
log entry generation. Anyway, if you aren't running on a 64-bit machine by
then, you'll deserve to lose.
G15. Is there a way in fetchmail to support disconnected IMAP mode?
No. Fetchmail is a mail transport agent, best understood as a protocol
gateway between POP3/IMAP servers and SMTP. Disconnected operation requires
an elaborate interactive client. It's a very different problem.
G16. How will fetchmail perform under heavy loads?
Fetchmail streams message bodies line-by-line; the most core it ever
requires per message is enough memory to hold the RFC822 header, and that
storage is freed when body processing begins. It is, accordingly, quite
economical in its use of memory.
After startup time, a fetchmail running in daemon mode stats its
configuration file once per poll cycle to see whether it has changed and
should be rescanned. Other than that, a fetchmail in normal operation
doesn't touch the disk at all; that job is left up to the MTA or MDA the
fetchmail talks to.
Fetchmail's performance is usually bottlenecked by latency on the POP server
or (less often) on the TCP/IP link to the server. This is not a problem
readily solved by tuning fetchmail, or even by buying more TCP/IP capacity
(which tends to improve bandwidth but not necessarily latency).
_________________________________________________________________
Build-time problems
[DEL: B1. Make coughs and dies when building on FreeBSD. :DEL]
As of release 6.3.0, fetchmail's Makefile[.in] should work flawlessly with
BSD's portable make used on FreeBSD. With older releases, use GNU make
(usually installed as gmake).
B2. Lex bombs out while building the fetchmail lexer.
fetchmail 6.3.0 and newer ship with the lexer and parser in .c formats, so
you do not need to use lex unless you hacked the .l or .y files.
fetchmail's lexer has been developed with GNU flex, and the lex tools
shipped by some UNIX vendors (HP, SGI, Sun) are known to be incapable of
compiling fetchmail's lexer.
B3. I get link failures when I try to build fetchmail.
If you get errors resembling these:
mxget.o(.text+0x35): undefined referenceto '__res_search'
mxget.o(.text+0x99): undefined reference to '__dn_skipname'
mxget.o(.text+0x11c): undefined reference to '__dn_expand'
mxget.o(.text+0x187): undefined reference to '__dn_expand'
make: *** [fetchmail] Error 1
then you must add "-lresolv" to the LOADLIBS line in your Makefile once you
have installed the 'bind' package.
If you get link errors involving dcgettext, like these:
rcfile_y.o: In function 'yyparse':
rcfile_y.o(.text+0x3aa): undefined reference to 'dcgettext__'
rcfile_y.o(.text+0x4f2): undefined reference to 'dcgettext__'
rcfile_y.o(.text+0x5ee): undefined reference to 'dcgettext__'
rcfile_y.o: In function 'yyerror':
rcfile_y.o(.text+0xc7c): undefined reference to 'dcgettext__'
rcfile_y.o(.text+0xcc8): undefined reference to 'dcgettext__'
rcfile_y.o(.text+0xdf9): more undefined references to 'dcgettext__' follow
install an up to date version of GNU gettext, reconfigure and rebuild
fetchmail. If that does not help, reconfigure with '--disable-nls' added to
the "./configure" command and rebuild.
B4. I get build failures in the intl directory.
Reconfigure with --disable-nls and recompile.
_________________________________________________________________
Fetchmail configuration file grammar questions
F1. Why does my old .fetchmailrc file no longer work?
If your file predates 5.8.9
If you were using ETRN mode, change your smtphost option to a fetchdomains
option.
If your file predates 5.8.3
The 'via localhost' special case for use with ssh tunnelling is gone. Use
the %h feature of plugin instead.
If your file predates 5.6.8
In 5.6.8, the preauth keyword and option were changed back to auth. The
preauth synonym will still be supported through a few more point releases.
If your file predates 5.6.5
The imap-gss, imap-k4, and imap-login protocol types are gone. This is a
result of a major re-factoring of the authentication machinery; fetchmail
can now use Kerberos V4 and GSSAPI not just with IMAP but with POP3 servers
that have RFC1734 support for the AUTH command.
When trying to identify you to an IMAP or POP mailserver, fetchmail now
first tries methods that don't require a password (GSSAPI, KERBEROS_IV);
then it looks for methods that mask your password (CRAM-MD5, X-OTP); and
only if it the server doesn't support any of those will it ship your
password en clair.
Setting the preauth option to any value other than 'password' will prevent
from looking for a password in your .netrc file or querying for it at
startup time.
If your file predates 5.1.0
In 5.1.0, the auth keyword and option were changed to preauth.
If your file predates 4.5.5
If the dns option is on (the default), you may need to make sure that any
hostname you specify (for mail hosts or for an SMTP target) is a canonical
fully-qualified hostname). In order to avoid DNS overhead and complications,
fetchmail no longer tries to derive the fetchmail client machine's canonical
DNS name at startup.
If your file predates 4.0.6:
Just after the 'via' option was introduced, I realized that the interactions
between the 'via', 'aka', and 'localdomains' options were out of control.
Their behavior had become complex and confusing, so much so that I was no
longer sure I understood it myself. Users were being unpleasantly surprised.
Rather than add more options or crock the code, I re-thought it. The
redesign simplified the code and made the options more orthogonal, but may
have broken some complex multidrop configurations.
Any multidrop configurations that depended on the name just after the 'poll'
or 'skip' keyword being still interpreted as a DNS name for address-matching
purposes, even in the presence of a 'via' option, will break.
It is theoretically possible that other unusual configurations (such as
those using a non-FQDN poll name to generate Kerberos IV tickets) might also
break; the old behavior was sufficiently murky that we can't be sure. If you
think this has happened to you, contact the maintainer.
If your file predates 3.9.5:
The 'remote' keyword has been changed to 'folder'. If you try to use the old
keyword, the parser will utter a warning.
If your file predates 3.9:
It could be because you're using a .fetchmailrc that's written in the old
popclient syntax without an explicit 'username' keyword leading the first
user entry attached to a server entry.
This error can be triggered by having a user option such as 'keep' or
'fetchall' before the first explicit username. For example, if you write
poll openmail protocol pop3
keep user "Hal DeVore" there is hdevore here
the 'keep' option will generate an entire user entry with the default
username (the name of fetchmail's invoking user).
The popclient compatibility syntax was removed in 4.0. It complicated the
configuration file grammar and confused users.
If your file predates 2.8:
The 'interface', 'monitor' and 'batchlimit' options changed after 2.8.
They used to be global options with 'set' syntax like the batchlimit and
logfile options. Now they're per-server options, like 'protocol'.
If you had something like
set interface = "sl0/10.0.2.15"
in your .fetchmailrc file, simply delete that line and insert 'interface
sl0/10.0.2.15' in the server options part of your 'defaults' declaration.
Do similarly for any 'monitor' or 'batchlimit' options.
F2. The .fetchmailrc parser won't accept my all-numeric user name.
Either upgrade to a post-5.0.5 fetchmail or put string quotes around it. :-)
The configuration file parser in older fetchmail versions treated any
all-numeric token as a number, which confused it when it was expecting a
name. String quoting forces the token's class.
The lexical analyzer in 5.0.6 and beyond is smarter and assumes any token
following "username" or "password" is a string.
F3. The .fetchmailrc parser won't accept my host or username beginning with
'no'.
See F2. You're caught in an unfortunate crack between the newer-style syntax
for negated options ('no keep', 'no rewrite' etc.) and the older style
run-on syntax ('nokeep', 'norewrite' etc.).
Upgrade to a 5.0.6 or later fetchmail, or put string quotes around your
token.
F4. I'm getting a 'parse error' message I don't understand.
The most common cause of mysterious parse errors is putting a server option
after a user option. Check the manual page; you'll probably find that by
moving one or more options closer to the 'poll' keyword you can eliminate
the problem.
Yes, I know these ordering restrictions are hard to understand.
Unfortunately, they're necessary in order to allow the 'defaults' feature to
work.
_________________________________________________________________
Configuration questions
C1. Why do I need a .fetchmailrc when running as root on my own machine?
Ian T. Zimmerman <itz@rahul.net> asked:
On the machine where I'm the only real user, I run fetchmail as root from a
cron job, like this:
fetchmail -u "itz" -p POP3 -s bolero.rahul.net
This used to work as is (with no .fetchmailrc file in root's home directory)
with the last version I had (1.7 or 1.8, I don't remember). But with 2.0, it
RECPs all mail to the local root user, unless I create a .fetchmailrc in
root's home directory containing:
skip bolero.rahul.net proto POP3
user itz is itz
It won't work if the second line is just "user itz". This is silly.
It seems fetchmail decides to RECP the 'default local user' (i.e. the uid
running fetchmail) unless there are local aliases, and the 'default' aliases
(itz->itz) don't count. They should.
Answer:
No they shouldn't. I thought about this for a while, and I don't much like
the conclusion I reached, but it's unavoidable. The problem is that
fetchmail has no way to know, in general, that a local user 'itz' actually
exists.
"Ah!" you say, "Why doesn't it check the password file to see if the remote
name matches a local one?" Well, there are two reasons.
One: it's not always possible. Suppose you have an SMTP host declared that's
not the machine fetchmail is running on? You lose.
Two: How do you know server itz and SMTP-host itz are the same person? They
might not be, and fetchmail shouldn't assume they are unless local-itz can
explicitly produce credentials to prove it (that is, the server-itz password
in local-itz's .fetchmailrc file.).
Once you start running down possible failure modes and thinking about ways
to tinker with the mapping rules, you'll quickly find that all the
alternatives to the present default are worse or unacceptably more
complicated or both.
C2. How can I arrange for a fetchmail daemon to get killed when I log out?
The easiest way to dispatch fetchmail on logout (which will work reliably
only if you have just one login going at any time) is to arrange for the
command 'fetchmail -q' to be called on logout. Under bash, you can arrange
this by putting 'fetchmail -q' in the file '~/.bash_logout'. Most csh
variants execute '~/.logout' on logout. For other shells, consult your shell
manual page.
Automatic startup/shutdown of fetchmail is a little harder to arrange if you
may have multiple login sessions going. In the contrib subdirectory of the
fetchmail distribution there is some shell code you can add to your
.bash_login and .bash_logout profiles that will accomplish this. Thank James
Laferriere <babydr@nwrain.net> for it.
Some people start up and shut down fetchmail using the ppp-up and ppp-down
scripts of pppd.
C3. How do I know what interface and address to use with --interface?
This depends a lot on your local networking configuration (and right now you
can't use it at all except under Linux and the newer BSDs). However, here
are some important rules of thumb that can help. If they don't work, ask
your local sysop or your Internet provider.
First, you may not need to use --interface at all. If your machine only ever
does SLIP or PPP to one provider, it's almost certainly by a point to point
modem connection to your provider's local subnet that's pretty secure
against snooping (unless someone can tap your phone or the provider's local
subnet!). Under these circumstances, specifying an interface address is
fairly pointless.
What the option is really for is sites that use more than one provider.
Under these circumstances, typically one of your provider IP addresses is
your mailserver (reachable fairly securely via the modem and provider's
subnet) but the others might ship your packets (including your password)
over unknown portions of the general Internet that could be vulnerable to
snooping. What you'll use --interface for is to make sure your password only
goes over the one secure link.
To determine the device:
1. If you're using a SLIP link, the correct device is probably sl0.
2. If you're using a PPP link, the correct device is probably ppp0.
3. If you're using a direct connection over a local network such as an
ethernet, use the command 'netstat -r' to look at your routing table.
Try to match your mailserver name to a destination entry; if you don't
see it in the first column, use the 'default' entry. The device name
will be in the rightmost column.
To determine the address and netmask:
1. If you're talking to slirp, the correct address is probably 10.0.2.15,
with no netmask specified. (It's possible to configure slirp to present
other addresses, but that's the default.)
2. If you have a static IP address, run 'ifconfig <device>', where <device>
is whichever one you've determined. Use the IP address given after "inet
addr:". That is the IP address for your end of the link, and is what you
need. You won't need to specify a netmask.
3. If you have a dynamic IP address, your connection IP will vary randomly
over some given range (that is, some number of the least significant
bits change from connection to connection). You need to declare an
address with the variable bits zero and a complementary netmask that
sets the range.
To illustrate the rule for dynamic IP addresses, let's suppose you're hooked
up via SLIP and your IP provider tells you that the dynamic address pool is
255 addresses ranging from 205.164.136.1 to 205.164.136.255. Then
interface "sl0/205.164.136.0/255.255.255.0"
would work. To range over any value of the last two octets (65536 addresses)
you would use
interface "sl0/205.164.0.0/255.255.0.0"
C4. How can I set up support for sendmail's anti-spam features?
This answer covers versions of sendmail from 8.9.3-20 (the version installed
in Red Hat 6.2) upwards. If you have an older version, upgrade to sendmail
8.9.
Stock sendmails can now do anti-spam exclusions based on a database of
filter rules. The human-readable form of the database is at
/etc/mail/access. The database itself is at /etc/mail/access.db.
The table itself uses email addresses, domain names, and network numbers as
keys. For example,
spammer@aol.com REJECT
cyberspammer.com REJECT
192.168.212 REJECT
would refuse mail from spammer@aol.com, any user from cyberspammer.com (or
any host within the cyberspammer.com domain), and any host on the
192.168.212.* network. (This feature can be used to do other things as well;
see the sendmail documentation for details)
To actually set up the database, run
makemap hash deny <deny
in /etc/mail.
To test, send a message to your mailing address from that host and then pop
off the message with fetchmail, using the -v argument. You can monitor the
SMTP transaction, and when the FROM address is parsed, if sendmail sees that
it is an address in spamlist, fetchmail will flush and delete it.
Under no circumstances put your mailhost or any host you accept mail from
using fetchmail into your reject file. You will lose mail if you do this!!!
C5. How can I poll some of my mailboxes more/less often than others?
Use the interval keyword on the ones that should be checked less often. For
example, if you do a poll every 5 minutes, and want to poll some mailboxes
every 5 minutes and some every 30 minutes, use something like this:
poll mainsite.example.com proto pop3 user ....
poll secondary.example.com proto pop3 interval 6 user ...
Then secondary.example.com will be polled every 6th time that
mainsite.example.com is polled, which with a polling interval of every 5
minutes means that secondary.example.com will be polled every 30 minutes.
Fetchmail works OK started up manually, but not from an init script.
Often, startup scripts have a different environment than an interactive
login shell. For instance, $HOME might point to "/root" when you are logged
in as root, but it might be either unset, or set to "/" when the startup
scripts are running. That means fetchmail at startup can't find the
.fetchmailrc.
Pick a location (such as /etc/fetchmailrc) and use fetchmail's -f option to
point fetchmail at it. That should solve the problem.
C7. How can I forward mail to another host?
To forward mail to a host other than the one you are running fetchmail on,
use the smtphost or smtpname option. See the manual page for details.
_________________________________________________________________
How to make fetchmail play nice with various MTAs
T1. How can I use fetchmail with sendmail?
For most sendmails, no special configuration is required. Eric Allman tells
me that if FEATURE(always_add_domain) is included in sendmail's
configuration, you can leave the rewrite option off.
If your sendmail complains "sendmail does not relay", make sure your
sendmail.cf file says Cwlocalhost so that sendmail recognizes 'localhost' as
a name of its host.
If you're mailing from another machine on your local network, also ensure
that its IP address is listed in ip_allow or name in name_allow (usually in
/etc/mail/)
If you find that your sendmail doesn't like the address
'FETCHMAIL-DAEMON@localhost' (which is used in the bouncemail that fetchmail
generates), you may have to set FEATURE(accept_unqualified_senders).
Günther Leber reports that Digital Unix sendmails won't work with fetchmail.
The symptom is an error message "553 Local configuration error, hostname not
recognized as local". The problem is that fetchmail normally feeds sendmail
with the client machine's host address in the MAIL FROM line. These
sendmails think this means they're seeing the result of a mail loop and
suppress the mail. You may be able to work around this by running in
--invisible mode.
If you want to support multidrop mode, and you can get access to your
mailserver's sendmail.cf file, it's a good idea to add this rule:
H?l?Delivered-To: $h
This will cause the mailserver's sendmail to reliably write the appropriate
envelope address into each message before fetchmail sees it, and tell
fetchmail which header it is. With this change, multidrop mode should work
reliably even when the Received header omits the envelope address (which
will typically be the case when the message has multiple recipients).
However it will still not distinguish the recipients, your only advantage is
that no bounce will be sent if a message is BCC addressed to multiple users
at your site. To fix even that problem, you might want to try the following
hack, which is however untested and quite experimental:
H?J?Delivered-To: $u
Mmdrop, P=/usr/bin/procmail, F=lsDFMqSPfhnu9J,
S=EnvFromSMTP/HdrFromSMTP, R=EnvToSMTP/HdrToSMTP,
T=DNS/RFC822/X-Unix,
A=procmail -Y -a $u -d $h
For both hacks, you have to declare 'envelope "Delivered-To:"' on the
fetchmail side, to put the virtual domain (e.g. 'domain.com') with RELAY
permission into your access file and to add a line reading 'domain.com
local:local-pop-user' for the first and 'domain.com mdrop:local-pop-user'
for the second hack to your mailertable.
You will notice that if the mail already has a Delivered-To header, sendmail
will not add another. Further, editing sendmail.cf directly is not very
comfortable. Solutions for both problems can be found in Peter 'Rattacresh'
Backes' 'hybrid' patch against sendmail. Have a look at it, you can find it
in the contrib subdirectory.
Feel free to try Martijn Lievaart's detailed recipe in the contrib
subdirectory of the fetchmail source distribution, it attempts to realize
multidrop mailboxes with an external script.
If for some reason you are invoking sendmail via the mda option (rather than
delivering to port 25 via smtp), don't forget to include the -i switch.
Otherwise you will occasionally get mysterious delivery failures with a
SIGPIPE as the sendmail instance dies. The problem is messages with a single
dot at start of a text line.
T2. How can I use fetchmail with qmail?
Turn on the forcecr option; qmail's listener mode doesn't like header or
message lines terminated with bare linefeeds.
(This information is thanks to Robert de Bath <robert@mayday.cix.co.uk>.)
If a mailhost is using the qmail package, then, providing the local hosts
are also using qmail, it is possible to set up one fetchmail link to be
reliably collect the mail for an entire domain.
One of the basic features of qmail is the 'Delivered-To:' message header.
Whenever qmail delivers a message to a local mailbox it puts the username
and hostname of the envelope recipient on this line. The major reason for
this is to prevent mail loops.
To set up qmail to batch mail for a disconnected site the ISP-mailhost will
have normally put that site in its 'virtualhosts' control file so it will
add a prefix to all mail addresses for this site. This results in mail sent
to 'username@userhost.userdom.dom.com' having a 'Delivered-To:' line of the
form:
Delivered-To: mbox-userstr-username@userhost.userdom.dom.com
A single host maildrop will be slightly simpler:
Delivered-To: mbox-userstr-username@userhost.dom.com
The ISP can make the 'mbox-userstr-' prefix anything they choose but a
string matching the user host name is likely.
To use this line you must:
1. Ensure the option 'envelope Delivered-To:' is in the fetchmail config
file.
2. Ensure you have a localdomains containing 'userdom.dom.com' or
'userhost.dom.com' respectively.
So far this reliably delivers messages to the correct machine of the local
network, to deliver to the correct user the 'mbox-userstr-' prefix must be
stripped off of the user name. This can be done by setting up an alias
within the qmail MTA on each local machine. Simply create a dot-qmail file
called '.qmail-mbox-userstr-default' in the alias directory (normally
/var/qmail/alias) with the contents:
| ../bin/qmail-inject -a -f"$SENDER" "${LOCAL#mbox-userstr-}@$HOST"
Note this does require a modern /bin/sh.
Peter Wilson adds:
"My ISP uses "alias-unzzippedcom-" as the prefix, which means that I need to
name my file ".qmail-unzzippedcom-default". This is due to qmail's
assumption that a message sent to user-xyz is handled by the file
~user/.qmail-xyz (or ~user/.qmail-default)."
Luca Olivetti adds:
If you aren't using qmail locally, or you don't want to set up the alias
mechanism described above, you can use the option 'qvirtual "mbox-userstr-"'
in your fetchmail config file to strip the prefix from the local user name.
T3. How can I use fetchmail with exim?
If you have rewrite on:
There is an RFC1123 requirement that MAIL FROM and RCPT TO addresses you
pass to it have to be canonical (e.g. with a fully qualified hostname part).
Therefore fetchmail tries to pass fully qualified RCPT TO addresses. But
exim does not by default accept 'localhost' as a fully qualified domain.
This can be fixed.
In exim.conf, add 'localhost' to your local_domains declaration if it's not
already present. For example, the author's site at thyrsus.com would have a
line reading:
local_domains = thyrsus.com:localhost
If you have rewrite off:
MAIL FROM is a potential problem if the MTAs upstream from your fetchmail
don't necessarily pass canonicalized From and Return-Path addresses, and
fetchmail's rewrite option is off. The specific case where this has come up
involves bounce messages generated by sendmail on your mailer host, which
have the (un-canonicalized) origin address MAILER-DAEMON.
The right way to fix this is to enable the rewrite option and have fetchmail
canonicalize From and Return-Path addresses with the mailserver hostname
before exim sees them. This option is enabled by default, so it won't be off
unless you turned it off.
If you must run with rewrite off, there is a switch in exim's configuration
files that allows it to accept domainless MAIL FROM addresses; you will have
to flip it by putting the line
sender_unqualified_hosts = localhost
in the main section of the exim configuration file. Note that this will
result in such messages having an incorrect domain name attached to their
return address (your SMTP listener's hostname rather than that of the remote
mail server).
T4. How can I use fetchmail with smail?
Smail 3.2 is very nearly plug-compatible with sendmail, and may work fine
out of the box.
We have one report that when processing multiple messages from a single
fetchmail session, smail sometimes delivers them in an order other than
received-date order. This can be annoying because it scrambles
conversational threads. This is not fetchmail's problem, it is an smail
'feature' and has been reported to the maintainers as a bug.
Very recent smail versions require an -smtp_hello_verify option in the smail
config file. This overrides smail's check to see that the HELO address is
actually that of the client machine, which is never going to be the case
when fetchmail is in the picture. According to RFC1123 an SMTP listener must
allow this mismatch, so smail's new behavior (introduced sometime between
3.2.0.90 and 3.2.0.95) is a bug.
You may also need to say -smtp_hello_broken_allow=127.0.0.1 in order for
smail to accept the "localhost" that fetchmail normally appends to recipient
addresses.
T5. How can I use fetchmail with SCO's MMDF?
MMDF itself is difficult to configure, but it turns out that connecting
fetchmail to MMDF's SMTP channel isn't that hard. You can read an MMDF
recipe that describes replacing a UUCP link with fetchmail feeding MMDF.
T6. How can I use fetchmail with Lotus Notes?
The Lotus Notes SMTP gateway tries to deduce when it should convert \n to
\r\n, but its rules are not the intuitive and correct-for-RFC822 ones. Use
'forcecr'.
T7. How can I use fetchmail with Courier IMAP?
The courier mta doesn't like RCPT addresses that look like
someone@localhost. Work around this with an smtphost or smtpaddress.
T8. How can I use fetchmail with vbmailshield?
vbmailshield's SMTP interpreter is broken. It doesn't understand RSET.
As a workaround, you can set batchlimit to 1 so RSET is never used.
_________________________________________________________________
How to make fetchmail work with various servers
S1. How can I use fetchmail with qpopper?
Qualcomm's qpopper is probably the best-of-breed among POP3 servers, and is
very widely deployed. Nevertheless, it has some problems which fetchmail
exposes. We recommend using IMAP instead if at all possible. If you must
talk to qpopper, here are some problems to be aware of:
Problems with retrieving large messages from qpopper 2.53
Tony Tang <tony@atn.com.hk> reports that there is a bad intercation between
fetchmail and qpopper 2.5.3 under Red Hat Linux versions 5.0 to 5.2, kernels
2.0.34 to 2.0.35. When fetching very large messages (over 700K) from 2.5.3,
fetchmail will hang with a socket error.
This is probably not a fetchmail bug, but rather a symptom of some problem
in the networking stack that qpopper's transmission pattern is tickling, as
fetchpop (another Linux POP client) also displays the hang but Netscape
running under Win95 does not. The problem can also be banished by upgrading
to qpopper 3.0b1.
Bad interaction with fetchmail 4.4.2 to 4.4.7
Versions of fetchmail from 4.4.2 through 4.4.7 had a bad interaction with
Eudora qpopper versions 2.3 and later. See X5 for details. The solution is
to upgrade your fetchmail.
S2. How can I use fetchmail with Microsoft Exchange?
It's been reliably reported that Exchange 2000's POP3 support is so broken
that it's unusable. One symptom is that messages without a terminating
newline get the POP3 message termination dot emitted -- you guessed it --
right after the last character of the message, with no terminating newline
added. This will hang fetchmail or any other RFC-compliant server. IMAP is
alleged to work OK, though.
Older versions of Exchange are semi-usable. They randomly drop attachments
on the floor, though. Microsoft acknowledges this as a known bug and
apparently has no plans to fix it.
Fetchmail using IMAP supports the proprietary NTLM mode used with M$
Exchange servers. To enable this, configure fetchmail with the --enable-NTLM
option and recompile it. Specify a user option value that looks like
'user@domain': the part to the left of the @ will be passed as the username
and the part to the right as the NTLM domain.
M$ Exchange violates the POP3 and IMAP RFCs. Its LIST command does not
reveal the real sizes of mail in the pop mailbox, but the sizes of the
compressed versions in the exchange mail database (thanks to Arjan De Vet
and Guido Van Rooij for alerting us to this problem).
Fetchmail works with M$ Exchange, despite this brain damage. Two features
are compromised. One is that the --limit option will not work right (it will
check against compressed and not actual sizes). The other is that a
too-small SIZE argument may be passed to your ESMTP listener, assuming
you're using one (this should not be a problem unless the actual size of the
message is above the listener's configured length limit).
Somewhat belatedly, I've learned that there's supposed to be a registry bit
that can fix this breakage:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MsExchangeIs\Parameters
System\Pop3 Compatibility
This is a bitmask that controls the variations from the standard protocol.
The bits defined are:
0x00000001:
Report exact message sizes for the LIST command
0x00000002:
Allow arbitrary linear whitespace between commands and arguments
0x00000004:
Enable the LAST command
0x00000008:
Allow an empty PASS command (needed for users with blank passwords,
but illegal in the protocol)
0x00000010:
Relax the length restrictions for arguments to commands (protocol
requires 40, but some user names may be longer than that).
0x00000020:
Allow spaces in the argument to the USER command.
There's another one that may be useful to know about:
KEY_LOCAL_MACHINE\System\CurrentControlSet\Services\MsExchangeIs\Parameters
System\Pop3 Performance
0x00000001:
Render messages to a temporary stream instead of sending directly
from the database (should always be on)
0x00000002: Flag unrenderable messages (instead of just failing commands)
(should only be on if you are seeing the problems reported in KB
Q168109)
0x00000004:
Return from the QUIT command before all messages have been deleted.
The Microsoft pod-person who revealed this information to me admitted that
he couldn't find it anywhere in their public knowledge base.
Another specific problem we have seen with Exchange servers has as its
symptom a response to LOGIN that says "NO Ambiguous Alias". Grant Edwards
writes:
This means that Exchange Server is too f*&#ing stupid to figure out which
mailbox belongs to you. Instead of actually keeping track of which inbox
belongs to which user, it uses some half-witted, guess-o-matic heuristic to
try to guess your mailbox name from your username.
In your case it doesn't work because your username maps to more than one
mailbox. For some people it doesn't work because their username maps to zero
mailboxes. This is yet another inept, lame, almost criminally negligent
design decision from our friends in Redmond.
You've got several options:
* Get your administrator to configure the server so that usernames and
mailbox names are the same.
* Get your administrator to add an alias that maps your username
explicitly to your mailbox name.
But, the best option involves a tactical nuclear weapon (an old ASROC will
do), pissing off a lot people who live downwind from Redmond, and your
choice of any Linux, NetBSD, FreeBSD, or Solaris CD-ROM.
S3. How can I use fetchmail with HP OpenMail?
No special configuration is required, but OpenMail versions prior to 6.0
have an annoying bug similar to the big one in Microsoft Exchange. The
message sizes it gives in the LIST are rounded to the nearest 1024 bytes. It
also has a nasty habit of discarding headers it doesn't recognize, such as
X- and Resent- headers.
As with M$ Exchange, the only real fix for these problems is to get a POP
(or preferably IMAP) server that isn't brain-dead. OpenMail's project
manager claims these bugs have been fixed in 6.0.
We've had a more recent report (December 2001) that the TOP command fails,
returning only one line regrardless of its argument, on something
identifying itself as "OpenMail POP3 interface".
S4. How can I use fetchmail with Novell GroupWise?
The Novell GroupWise IMAP server would be better named GroupFoolish; it is
(according to the designer of IMAP) unusably broken. Among other things, it
doesn't include a required content length in its BODY[TEXT] response.
Fetchmail works around this problem, but we strongly recommend voting with
your dollars for a server that isn't brain-dead. If you stick with code as
shoddy as GroupWise seems to be, you will probably pay for it with other
problems.
S5. How can I use fetchmail with InterChange?
You can't. At least not if you want to be able to see attachments.
InterChange has a bug similar to the MailMax server; it reports the message
length with attachments but doesn't download them on TOP or RETR.
On Jan 9 2001, the people at InfiniteMail sent me mail informing me that
their new 3.61.08 release of InterChange fixes this problem. I don't have
any reports one way or the other yet.
S6. How can I use fetchmail with MailMax?
You can't. At least not if you want to be able to see attachments. MailMax
has a bug; it reports the message length with attachments but doesn't
download them on TOP or RETR.
Also, we're told that TOP sometimes fails to retrieve the entire message
even when enough lines have been specified. The MailMax developers have
acknowledged this bug as of 4 May 2000, but there is no fix yet. If you must
use this server, force RETR with the fetchall option.
S7. How can I use fetchmail with FTGate?
The FTGate V2 server (and possibly older versions as well) has a weird bug.
It answers OK twice to a TOP request! Use the fetchall option to force use
of RETR and work around this bug.
_________________________________________________________________
How to fetchmail work with specific ISPs
I1. How can I use fetchmail with CompuServe RPA?
First, make sure your fetchmail has the RPA support compiled in. Stock
fetchmail binaries (such as you might get from an RPM) don't. You can check
this by looking at the output of fetchmail -V; if you see the string "+RPA"
after the version ID you're good to go, otherwise you'll have to build your
own from sources (see the INSTALL file in the source distribution for
directions).
Give your CompuServe pass-phrase in lower case as your password. Add
'@compuserve.com' to your user ID so that it looks like 'user
<UserID>@compuserve.com', where <UserID> can be either your numerical userID
or your E-mail nickname. An RPA-enabled fetchmail will automatically check
for csi.com in the POP server's greeting line. If that's found, and your
user ID ends with '@compuserve.com', it will query the server to see if it
is RPA-capable, and if so do an RPA transaction rather than a plain-text
password handshake.
Warning: the debug (-v -v) output of fetchmail will show your pass-phrase in
Unicode!
These two .fetchmailrc entries show the difference between an RPA and
non-RPA configuration:
# This version will use RPA
poll csi.com via "pop.site1.csi.com" with proto POP3 and options no dns
user "CSERVE_USER@compuserve.com" there with password "CSERVE_PASSWORD"
is LOCAL_USER here options fetchall stripcr
# This version will not use RPA
poll non-rpa.csi.com via "pop.site1.csi.com" with proto POP3 and options no dns
user "CSERVE_USER" there with password "CSERVE_POP3_PASSWORD"
is LOCAL_USER here options fetchall stripcr
I2. How can I use fetchmail with Demon Internet's SDPS?
Single-drop mode
You can get fetchmail to download the email for just one user from Demon
Internet's POP3 server by giving it a username consisting of your Demon user
name followed by your account name, with an at-sign between them.
For example, to download email for the user <philh@vision25.demon.co.uk>,
you could use the following .fetchmailrc file:
set postmaster "philh"
poll pop3.demon.co.uk with protocol POP3:
user "philh@vision25" is philh
Multi-drop mode
Demon Internet's SDPS service is an implementation of POP3. All messages
have a Received: header added when they enter the maildrop, like this:
Received: from punt-1.mail.demon.net by mailstore for fred@xyz.demon.co.uk
id 899963657:10:27896:0; Thu, 09 Jul 98 05:54:17 GMT
To enable multi-drop mode you need to tell fetchmail that 'mailstore' is the
name of the host which accepted the mail, and let it know the hostname
part(s) of your E-mail address. The following example assumes that your
hostname is xyz.demon.co.uk, and that you have also bought "mail forwarding"
for the domain my-company.co.uk (in which case your MTA must also be
configured to accept mail sent to user@my-company.co.uk)
poll pop3.demon.co.uk proto pop3 aka mailstore no dns:
localdomains xyz.demon.co.uk my-company.co.uk
user xyz is *
Note that Demon may delete mail on the server which is more than 30 days
old; see their POP3 page for details.
The SDPS extension
There's a different way to do multidrop. It's not necessary on Demon
Internet, since fetchmail can parse Received addresses, but the person who
implemented this didn't know that. It may be useful if Demon Internet ever
changes mail transports.
SDPS includes a non-standard extension for retrieving the envelope of a
message (*ENV), which fetchmail optionally supports if compiled with the
--enable-SDPS option. If you have it, the first line of the fetchmail -V
response will include the string "+SDPS".
Once you have SDPS compiled in, fetchmail in POP3 mode will automatically
detect when it's talking to a Demon Internet host in multidrop mode, and use
the *ENV extension to get an envelope To address.
The autodetection works by looking at the hostname in the POP3 greeting
line; if you're accessing Demon Internet through a proxy it may fail. To
force SDPS mode, pick "sdps" as your protocol.
I3. How can I use fetchmail with usa.net's servers?
Enable 'fetchall'. A user reports that the 2.2 version of USA.NET's POP
server reports that you must use the 'fetchall' option to make sure that all
of the mail is retrieved, otherwise some may be left on the server. This is
almost certainly a server bug.
The usa.net servers (at least in their 2.2 version, June 1998) don't handle
the TOP command properly, either. Regardless of the argument you give it,
they retrieve only about 10 lines of the message. Fetchmail normally uses
TOP for message retrieval in order to avoid marking messages seen, but
'fetchall' forces it to use RETR instead.
Also, we're told USA.NET adds a ton of hops to your messages. You may need
to raise the MaxHopCount parameter in your sendmail.cf to avoid having
fetched mail rejected.
(Note: Other failure modes have been reported on usa.net's servers. They
seem to be chronically flaky. We recommend finding another provider.)
I4. How can I use fetchmail with geocities POP3 servers?
Nathan Cutler reports that the the mail.geocities.com POP3 servers fail to
include the first Received line of the message in the send to fetchmail.
This can solve problems if your MUA interprets Received continuations as
body lines and doesn't parse any of the following headers.
Workaround is to use "mda" keyword or "--mda" switch:
mda "sed -e '1s/^\t/Received: /' | formail | /usr/bin/procmail -d <user>"
Replace \t with exactly one tabulation character.
You should also consider using "fetchall" option because Geocities' servers
sometimes think that the first 45 messages have already been read.
Fix: Get an email provider that doesn't suck. The pop-up ads on Geocities
are lame, you should boycott them anyway.
I5. How can I use fetchmail with Hotmail or Lycos Webmail?
You can't directly. But you can use fetchmail with hotmail or lycos webmail
with the help of the HotWayDaemon daemon. You don't even need to install
hotwayd as a daemon in inetd.conf but can use it as a plugin. Your
configuration should look like this:
poll localhost protocol pop3 tracepolls
plugin "/usr/local/sbin/hotwayd -l 0 -p yourproxy:yourproxyport"
username "youremail@hotmail.com" password "yourpassword"
fetchall
As a second option you may consider using gotmail.
I6. How can I use fetchmail with MSN?
You can't. MSN uses something that looks like POP3, except the
authentication part is nonstandard. And of course they don't document it, so
nobody but their Windows clients can speak it.
This is a customer lock-in tactic; we recommend boycotting MSN as the only
appropriate response.
As of 5.0.8, we have support for the client side of NTLM authentication.
It's possible this may enable fetchmail to talk to MSN; if so, somebody
should report it so this FAQ can be corrected.
I7. How can I use fetchmail with SpryNet?
The SpryNet POP3 servers mark a message queried with TOP as seen. This means
that if your connection drops in mid-message, it may end up invisibly stuck
on your mail spool. Use the fetchall flag to ensure that it's recovered on
the next cycle.
I8. How can I use fetchmail with comcast.net or other Maillennium servers?
Stock fetchmail will work with a Maillennium POP3/PROXY server... but this
server will truncate "TOP" responses after 64 - 82 kB (we have varying
reports), in violation of Internet Standard #53 aka. RFC-1939 (POP3). Don't
mistake this for a fetchmail bug. (Reported July 2003.) Comcast documented
they haven't understood what this is about in two messages from April 2004.
Beginning with version 6.3.2, fetchmail will fall back to the RETR command
if the greeting string contains "Maillennium POP3/PROXY server", and print a
warning message. This means however that fetchmail has no means to prevent
the "seen" flag from being set on the server (Note that officially, POP3 has
no notion of seen tracking, but it works for some sites.)
Workaround for older versions: use the fetchall option.
_________________________________________________________________
How to set up well-known security and authentication methods
K1. How can I use fetchmail with SOCKS?
Giuseppe Guerini added a --with-socks option that supports linking with
socks library. If you specify the value of this option as "yes", the
configure script will try to find the Rconnect library and set the makefile
up to link it. You can also specify a directory containing the Rconnect
library.
Alan Schmitt has added a similar --with-socks5 option that may work better
if you have a recent version of the SOCKS library.
K2. How can I use fetchmail with IPv6 and IPsec?
To use fetchmail with IPv6, you need a system that supports IPv6, the "Basic
Socket Interface Extensions for IPv6" (RFC 2133).
The NRL IPv6+IPsec software distribution can be obtained from:
http://web.mit.edu/network/isakmp/
More information on using IPv6 with Linux can be obtained from:
* http://www.bieringer.de/linux/IPv6/IPv6-HOWTO/IPv6-HOWTO.html
K3. How can I get fetchmail to work with ssh?
Use the plugin option. This is dead simple with IMAP:
plugin "ssh %h /usr/sbin/imapd"
You may have to use a different absolute pathname, whatever the location of
imapd on your mailserver is. This option tells fetchmail that instead of
opening a connection on the server's port 143 and doing standard IMAP
authentication, fetchmail should ssh to the server and run imapd, using the
more secure ssh authentication (as well as getting ssh's end-to-end
encryption). Most IMAP daemons will detect that they've been called from the
command line and assume the connection is preauthenticated.
POP3 daemons aren't quite as smart. They won't know they are
preauthenticated in this mode, so you'll actually have to ship your
password. It will be under ssh encryption, though, so that shouldn't be a
problem.
K4. What do I have to do to use the IMAP-GSS protocol?
Fetchmail can use RFC1731 GSSAPI authorization to safely identify you to
your IMAP server, as long as you can share Kerberos V credentials with your
mail host and you have a GSSAPI-capable IMAP server. UW-IMAP (available via
FTP at ftp.cac.washington.edu) is the only one I'm aware of and the one I
recommend anyway for other reasons. You'll need version 4.1-FINAL or greater
though, and it has to have GSS support compiled in.
Neither UW-IMAP nor fetchmail compile in support for GSS by default, since
it requires libraries from the Kerberos V distribution (available via FTP at
athena-dist.mit.edu). If you have these, compiling in GSS support is simple:
add a --with-gssapi=[/path/to/krb5/root] option to configure. For instance,
I have all of my Kerberos V libraries installed under /usr/krb5 so I run
configure --with-gssapi=/usr/krb5
Setting up Kerberos V authentication is beyond the scope of this FAQ (you
may find Jim Rome's paper How to Kerberize your site helpful), but you'll at
least need to add a credential for imap/[mailhost] to the keytab of the mail
server (IMAP doesn't just use the host key). Then you'll need to have your
credentials ready on your machine (cf. kinit).
After that things are very simple. Set your protocol to imap-gss in your
.fetchmailrc, and omit the password, since imap-gss doesn't need one. You
can specify a username if you want, but this is only useful if your mailbox
belongs to a username different from your Kerberos principal.
Now you don't have to worry about your password appearing in cleartext in
your .fetchmailrc, or across the network.
K5. How can I use fetchmail with SSL?
You'll need to have the OpenSSL libraries installed. Configure with
--with-ssl. If you have the OpenSSL libraries installed in the default
location (/usr/local/ssl) ths will suffice. If you have them installed in a
non-default location, you'll need to specify it as an argument to --with-ssl
after an equal sign.
Note that there is a known bug in the implementation of SSL_peek under
OpenSSL versions 0.9.5 and older that fetchmail occasionally tripped over,
causing hangs. It is recommended that you install 0.9.6 or later.
Fetchmail binaries built this way support ssl, sslkey, and sslcert options
that control SSL encryption. You will need to have an SSL-enabled mailserver
to use these options. See the manual page for details and some words of care
on the limited security provided.
If your open OpenSSL session dies with a message that complains "PRNG not
seeded", update or improve your operating system. This means that the
OpenSSL library on your machine has been unable to locate a source of random
bits from which to seed its random-number generator; normally these come
from the /dev/urandom, and this message probably means your OS doesn't have
that device.
An interactive program could seed the random number generator from keystroke
timings or some other form of user input. Because fetchmail is primarily
designed to run forever as a background daemon, that option is not available
in this case.
If you don't have the libraries installed, but do have the OpenSSL utility
toolkit, something like this may work:
poll MYSERVER port 993 plugin "openssl s_client -connect %h:%p"
protocol imap username MYUSERNAME password MYPASSWORD
You should note that SSL is only secure against a "man-in-the-middle" attack
if the client is able to verify that the peer's public key is the correct
one, and has not been substituted by an attacker. fetchmail can do this in
one of two ways: by verifying the SSL certificate, or by checking the
fingerprint of the peer's public key.
There are three parts to SSL certificate verification: checking that the
domain name in the certificate matches the hostname you asked to connect to;
checking that the certificate expiry date has not passed; and checking that
the certificate has been signed by a known Certificate Authority (CA). This
last step takes some preparation, as you need to install the root
certificates of all the CA's which you might come across.
The easiest way to do this is using the root CA keys supplied in the OpenSSL
distribution, which means you need to download and unpack the source tarball
from www.openssl.org. Once you have done that:
1. mkdir /etc/ssl/certs
2. in the openssl-x.x.x/certs directory: cp *.pem /etc/ssl/certs/
3. in the openssl-x.x.x/tools directory: edit c_rehash and set
$dir="/etc/ssl"
4. run "perl c_rehash". This generates a number of symlinks within the
/etc/ssl/certs/ directory
Now in .fetchmailrc, set option sslcertpath to point to this directory:
poll pop3.example.com proto pop3 uidl no dns
user foobar@example.com password xyzzy is foobar ssl sslcertpath /etc/ssl/cer
ts
If the server certificate has not been signed by a known CA (e.g. it is a
self-signed certificate), then this certificate validation will always fail.
Certificate verification is always attempted. If it fails, by default a
warning is printed but the connection carries on (which means you are not
protected against attack). If your server's certificate has been properly
set up and verifies correctly, then add the "sslcertck" option to enforce
validation. If your server doesn't have a valid certificate though (e.g. it
has a self-signed certificate) then it will never verify, and the only way
you can protect yourself is by checking the fingerprint.
To check the peer fingerprint: first use fetchmail -v once to connect to the
host, at a time when you are pretty sure that there is no attack in progress
(e.g. you are not traversing any untrusted network to reach the server).
Make a note of the fingerprint shown. Now embed this in your .fetchmailrc
using the sslfingerprint option: e.g.
poll pop3.example.com proto pop3 uidl no dns
user foobar@example.com password xyzzy is foobar
ssl sslfingerprint "67:3E:02:94:D3:5B:C3:16:86:71:37:01:B1:3B:BC:E2"
When you next connect, the public key presented by the server will be
verified against the fingerprint given. If it's different, it may mean that
a man-in-the-middle attack is in progress - or it might just mean that the
server changed its key. It's up to you to determine which has happened.
K6. How can I tell fetchmail not to use TLS if the server advertises it?
Some servers advertise STLS (POP3) or STARTTLS (IMAP), and fetchmail will
automatically attempt TLS negotiation if SSL was enabled at compile time.
This can however cause problems if the upstream didn't configure his
certificates properly.
In order to prevent fetchmail from trying TLS (STLS, STARTTLS) negotiation,
add this option:
sslproto ssl23
This restricts fetchmail's SSL/TLS protocol choice from the default "SSLv2,
SSLv3, TLSv1" to the two SSL variants, disabling TLSv1. Note however that
this causes the connection to be unencrypted unless an encrypting "plugin"
is used or SSL is requested explicitly.
_________________________________________________________________
Runtime fatal errors
R1. Fetchmail isn't working, and -v shows 'SMTP connect failed' messages.
Fetchmail itself is probably working, but your SMTP port 25 listener is down
or inaccessible.
The first thing to check is if you can telnet to port 25 on your smtp host
(which is normally 'localhost' unless you've specified an smtp option in
your .fetchmailrc or on the command line) and get a greeting line from the
listener. If the SMTP host is inaccessible or the listener is down, fix that
first.
In Red Hat Linux 6.x, SMTP is disabled by default. To fix this, set
"DAEMON=yes" in your /etc/sysconfig/sendmail file, then restart sendmail by
running "/sbin/service sendmail restart".
If the listener seems to be up when you test with telnet, the most benign
and typical problem is that the listener had a momentary seizure due to
resource exhaustion while fetchmail was polling it -- process table full or
some other problem that stopped the listener process from forking. If your
SMTP host is not 'localhost' or something else in /etc/hosts, the fetchmail
glitch could also have been caused by transient nameserver failure.
Try running fetchmail -v again; if it succeeds, you had one of these kinds
of transient glitch. You can ignore these hiccups, because a future
fetchmail run will get the mail through.
If the listener tests up, but you have chronic failures trying to connect to
it anyway, your problem is more serious. One way to work around chronic SMTP
connect problems is to use --mda. But this only attacks the symptom; you may
have a DNS or TCP routing problem. You should really try to figure out
what's going on underneath before it bites you some other way.
We have one report (from toby@eskimo.com) that you can sometimes solve such
problems by doing an smtp declaration with an IP address that your routing
table maps to something other than the loopback device (he used ppp0).
We also have a report that this error can be caused by having an /etc/hosts
file that associates your client host name with more than one IP address.
It's also possible that your DNS configuration isn't looking at /etc/hosts
at all. If you're using libc5, look at /etc/resolv.conf; it should say
something like:
order hosts,bind
so your /etc/hosts file is checked first. If you're running GNU libc6, check
your /etc/nsswitch.conf file. Make sure it says something like
hosts: files dns
again, in order to make sure /etc/hosts is seen first.
If you have a hostname set for your machine, and this hostname does not
appear in /etc/hosts, you will be able to telnet to port 25 and even send a
mail with rcpt to: user@host-not-in-/etc/hosts, but fetchmail can't seem to
get in touch with sendmail, no matter what you set smtpaddress to.
We had another report from a Linux user of fetchmail 2.1 who solved his SMTP
connection problem by removing the reference to -lresolv from his link line
and relinking. Apparently in some older Linux distributions the libc bind
library version works better.
As of 2.2, the configure script has been hacked so the bind library is
linked only if it is actually needed. So under Linux it won't be, and this
particular cause should go away.
R2. When I try to configure an MDA, fetchmail doesn't work.
(I hear this one from people who have run into the blank-line problem in
X1.)
Try sending yourself test mail and retrieving it using the command-line
options '-k -m cat'. This will dump exactly what fetchmail retrieves to
standard output (plus the Received line fetchmail itself adds to the
headers).
If the dump doesn't match what shows up in your mailbox when you configure
an MDA, your MDA is mangling the message. If it doesn't match what you sent,
then fetchmail or something on the server is broken.
R3. Fetchmail dumps core when given an invalid rc file.
This is usually reported from AIX or Ultrix, but has even been known to
happen on Linuxes without a recent version of flex installed. The problem
appears to be a result of building with an archaic version of lex.
Workaround: fix the syntax of your .fetchmailrc file.
Fix: build and install the latest version of flex.
R4. Fetchmail dumps core in -V mode, but operates normally otherwise.
We've had this reported to us under Linux using libc-5.4.17 and gcc-2.7.2.
It does not occur with libc-5.3.12 or earlier versions.
Workaround: link with GNU malloc rather than the stock C library malloc.
We're told there is some problem with the malloc() code in that version
which makes it fragile in the presence of multiple free() calls on the same
pointer (the malloc arena gets corrupted). Unfortunately it appears from
doing gdb traces that whatever free() calls producing the problem are being
made by the C library itself, not the fetchmail code (they're all from
within fclose, and not an fclose called directly by fetchmail, either).
R5. Running fetchmail in daemon mode doesn't work.
We have one report from a SunOS 4.1.4 user that trying to run fetchmail in
detached daemon mode doesn't work, but that using the same options with -N
(nodetach) is OK. We have another report of similar behavior from one Linux
user, but many other Linux users reportt no problem.
If this happens, you have a specific portability problem with the code in
daemon.c that detaches and backgrounds the daemon fetchmail. The isolated
Linux case has been chased down to a failure in dup(2) that may reflect a
glibc bug.
As a workaround, you can start fetchmail with -N and an ampersand to
background it. A Sun user recommends this:
(fetchmail --nodetach <other params> &)
The extra pair of parens is significant --- it makes sure that the process
detaches from the initial shell (one more shell is started and dies
immediately, detaching fetchmail and making it child of PID 1). This is
important when you start fetchmail interactively and than quit interactive
shell. The line above makes sure fetchmail lives after that!
R6. Fetchmail randomly dies with socket errors.
Check the MTU value in your PPP interface reported by /sbin/ifconfig. If
it's over 600, change it in your PPP options file. (/etc/ppp/options on my
box). Here are option values that work:
mtu 552
mru 552
Another circumstance that can trigger this is if you are polling a
virtual-mail-server name that is round-robin connected to different actual
servers, so you get different IP addresses on different poll cycles. To work
around this, change the poll name either to the real name of one of the
servers in the ring or to a corresponding IP address.
R7. Fetchmail running as root stopped working after an OS upgrade
In RH 6.0, the HOME value in the boot-time root environment changed from
/root to / as the result of a change in init. Move your .fetchmailrc or use
a -f option to explicitly point at the file. (Oddly, a similar problem has
been reported from Debian systems.)
R8. Fetchmail is timing out after fetching certain messages but before deleting
them
There's a TCP/IP stalling problem under Redhat 6.0 (and possibly other
recent Linuxes) that can cause this symptom. Brian Boutel writes:
TCP timestamps are turned on on my Linux boxes (I assume it's now the
default). This uses 12 extra bytes per segment. When the tcp connection
starts, the other end agrees a MSS of 1460, and then fragments 1460 byte
chunks into 1448 and 12, because is is not allowing for the timestamp.
Then, for reasons I can't explain, it waits a long time (typically 2
minutes) after the ack is sent before sending the next (fragmented)
packet. Turning off tcp timestamps avoids the fragmentation and restores
normal behaviour. To do this, [execute]
echo 0 > /proc/sys/net/ipv4/tcp_timestamps
I'm still unclear about the details of why this is happening. At least
[now] I am now getting good performance and no queue blocking.
R9. Fetchmail is timing out during message fetches
This is probably a general networking issue. Sending a "RETR" command will
cause the server to start sending large amounts of data, which means large
packets. If your networking layer has a packet-fragmentation problem, that's
where you'll see it.
R10. Fetchmail is dying with SIGPIPE.
This probably means you have an mda option. Your MDA is croaking while being
passed a message. Best fix is to remove the mda option and pass mail to your
port 25 SMTP listener.
If for some reason you are invoking sendmail via the mda option (rather than
delivering to port 25 via smtp), don't forget to include the -i switch.
Otherwise you will occasionally get mysterious delivery failures with a
SIGPIPE as the sendmail instance dies. The problem is messages with a single
dot at start of a text line.
R11. My server is hanging or emitting errors on CAPA.
Your POP3 server is broken. You can work around this with the declaration
auth password in your .fetchmailrc.
R12. Fetchmail isn't working and reports getaddrinfo errors.
1. Make sure you haven't mistyped the host name or address, and that your
DNS is working. If you cannot fix DNS, give the numeric host literal,
for instance, 192.168.0.1
2. Make sure your /etc/services file (or other services database) contains
the necessary service entries. If you cannot fix the services database,
use the --service option and give the numeric port address. Common port
addresses are:
service port
IMAP 143
IMAP+SSL 993
POP3 110
POP3+SSL 995
_________________________________________________________________
Hangs and lockups
H1. Fetchmail hangs when used with pppd.
Your problem may be with pppd's 'demand' option. We have a report that
fetchmail doesn't play well with it, but works with pppd if 'demand' is
turned off. We have no idea why this is.
H2. Fetchmail hangs during the MAIL FROM exchange.
The symptom: 'fetchmail -v' retrieves mail fine, but appears to hang after
sending the MAIL FROM command
SMTP> MAIL FROM: <someone@somewhere>
The hang is actually occuring when sendmail looks up a sender's address in
DNS. The problem isn't in fetchmail but in the configuration of sendmail.
You must enable the 'nodns' and 'nocanonify' features of sendmail.
Here was my fix for RedHat 7.2:
1. # cd /etc/mail
2. # cp sendmail.mc sendmail-mine.mc
3. Edit sendmail-mine.mc and add lines:
FEATURE(nodns)
FEATURE(nocanonify)
4. Build a new sendmail.cf
# m4 sendmail-mine.cf > /etc/sendmail.cf
5. Restart sendmail.
For more details consult the file /usr/share/sendmail-cf/README.
H3. Fetchmail hangs while fetching mail.
The symption: 'fetchmail -v' retrieves the first few messages, but hangs
returning:
fetchmail: SMTP< 550 5.0.0 Access denied
fetchmail: SMTP> RSET
fetchmail: SMTP< 250 2.0.0 Reset state
.......fetchmail: flushed
fetchmail: POP3> DELE 1
fetchmail: POP3< +OK marked deleted
Check and see if you're allowing sendmail connections through TCP wrappers.
Adding 'sendmail : 127.0.0.1' to /etc/hosts.allow could solve this problem.
_________________________________________________________________
Disappearing mail
D1. I think I've set up fetchmail correctly, but I'm not getting any mail.
Maybe you have a .forward or alias set up that you've forgotten about. You
should probably remove it.
Or maybe you're trying to run fetchmail in multidrop mode as root without a
.fetchmailrc file. This doesn't do what you think it should; see question
C1.
Or you may not be connecting to the SMTP listener. Run fetchmail -v and see
R1.
Or you may have your local user set incorrectly. In the following line
user 'remoteuser' there with password '*' is 'localuser' here
make sure that 'localuser' does exist and can receive mail.
D2. All my mail seems to disappear after a dropped connection.
One POP3 daemon used in the Berkeley Unix world that reports itself as POP3
version 1.004 actually throws the queue away. 1.005 fixed that. If you're
running this one, upgrade immediately. (It also truncates long lines at
column 1024)
Many POP servers, if an interruption occurs, will restore the whole mail
queue after about 10 minutes. Others will restore it right away. If you have
an interruption and don't see it right away, cross your fingers and wait ten
minutes before retrying.
Some servers (such as Microsoft's NTMail) are mis-designed to restore the
entire queue, including messages you have deleted. If you have one of these
and it flakes out on you a lot, try setting a small --fetchlimit value. This
will result in more IP connects to the server, but will mean it actually
executes changes to the queue more often.
Qualcomm's qpopper, used at many BSD Unix sites, is better behaved. If its
connection is dropped, it will first execute all DELE commands as though you
had issued a QUIT (this is a technical violation of the POP3 RFCs, but a
good idea in a world of flaky phone lines). Then it will re-queue any
message that was being downloaded at hangup time. Still, qpopper may require
a noticeable amount of time to do deletions and clean up its queue.
(Fetchmail waits a bit before retrying in order to avoid a 'lock busy'
error.)
D3. Mail that was being fetched when I interrupted my fetchmail seems to have
been vanished.
Fetchmail only sends a delete mail request to the server when either (a) it
gets a positive delivery acknowledgment from the SMTP listener, or (b) it
gets one of the spam-filter errors (see the description of the antispam>
option) from the listener. No interrupt can cause it to lose mail.
However, IMAP2bis has a design problem in that its normal fetch command
marks a message 'seen' as soon as the fetch command to get it is sent down.
If for some reason the message isn't actually delivered (you take a line hit
during the download, or your port 25 listener can't find enough free disk
space, or you interrupt the delivery in mid-message) that 'seen' message can
lurk invisibly in your server mailbox forever.
Workaround: add the 'fetchall' keyword to your fetch options.
Solution: switch to an IMAP4 server.
_________________________________________________________________
Multidrop-mode problems
M1. I've declared local names, but all my multidrop mail is going to root
anyway.
Somehow your fetchmail is never recognizing the hostname part of recipient
names it parses out of To/Cc/envelope-header lines as matching the name of
the mailserver machine. To check this, run fetchmail in foreground with -v
-v on. You will probably see a lot of messages with the format "line
rejected, %s is not an alias of the mailserver" or "no address matches;
forwarding to %s."
These errors usually indicate some kind of DNS configuration problem either
on the server or your client machine.
The easiest workaround is to add a 'via' option (if necessary) and add
enough aka declarations to cover all of your mailserver's aliases, then say
'no dns'. This will take DNS out of the picture (though it means mail may be
uncollected if it's sent to an alias of the mailserver that you don't have
listed).
It would be better to fix your DNS, however. DNS problems can hurt you in
lots of ways, for example by making your machines intermittently or
permanently unreachable to the rest of the net.
Occasionally these errors indicate the sort of header-parsing problem
described in M7.
M2. I can't seem to get fetchmail to route to a local domain properly.
A lot of people want to use fetchmail as a poor man's internetwork mail
gateway, picking up mail accumulated for a whole domain in a single server
mailbox and then routing based on what's in the To/Cc/Bcc lines.
In general, this is not really a good idea. It would be smarter to just let
the mail sit in the mailserver's queue and use fetchmail's ETRN or ODMR
modes to trigger SMTP sends periodically (of course, this means you have to
poll more frequently than the mailserver's expiration period). If you can't
arrange this, try setting up a UUCP feed.
If neither of these alternatives is available, multidrop mode may do (though
you are going to get hurt by some mailing list software; see the caveats
under THE USE AND ABUSE OF MULTIDROP MAILBOXES on the man page). If you want
to try it, the way to do it is with the 'localdomains' option.
In general, if you use localdomains you need to make sure of two other
things:
1. You've actually set up your .fetchmailrc entry to invoke multidrop mode.
Many people set a 'localdomains' list and then forget that fetchmail wants
to see more than one name (or the wildcard '*') in a 'here' list before it
will do multidrop routing.
2. You may have to set 'no envelope'.
Normally, multidrop mode tries to deduce an envelope address from a message
before parsing the To/Cc/Bcc lines (this enables it to avoid losing to
mailing list software that doesn't put a recipient address in the To lines).
Some ways of accumulating a whole domain's messages in a single server
mailbox mean it all ends up with a single envelope address that is useless
for rerouting purposes. You may have to set 'no envelope' to prevent
fetchmail from being bamboozled by this.
Check also answer T1 on a reliable way to do multidrop delivery if your ISP
(or your mail redirection provider) is using qmail.
M3. I tried to run a mailing list using multidrop, and I have a mail loop!
This isn't fetchmail's fault. Check your mailing list. If the list expansion
includes yourself or anybody else at your mailserver (that is, not on the
client side) you've created a mail loop. Just chop the host part off any
local addresses in the list.
If you use sendmail, you can check the list expansion with sendmail -bv.
M4. My multidrop fetchmail seems to be having DNS problems.
We have one report from a Linux user (not the same one as in R1!) who solved
this problem by removing the reference to -lresolv from his link line and
relinking. Apparently in some older Linux distributions the libc5 bind
library version works better.
As of 2.2, the configure script has been hacked so the bind library is
linked only if it is actually needed. So under Linux it won't be, and this
problem should go away.
M5. I'm seeing long DNS delays before each message is processed.
Use the 'aka' option to pre-declare as many of your mailserver's DNS names
as you can. When an address's host part matches an aka name, no DNS lookup
needs to be done to check it.
If you're sure you've pre-declared all of your mailserver's DNS names, you
can use the 'no dns' option to prevent other hostname parts from being
looked up at all.
Sometimes delays are unavoidable. Some SMTP listeners try to call DNS on the
From-address hostname as a way of checking that the address is valid.
M6. How do I get multidrop mode to work with majordomo?
In order for sendmail to execute the command strings in the majordomo alias
file, it is necessary for sendmail to think that the mail it receives via
SMTP really is destined for a local user name. A normal virtual-domain setup
results in delivery to the default mailbox, rather than expansion through
majordomo.
Michael <michael@bizsystems.com> gave us a recipe for dealing with this case
that pairs a run control file like this:
poll your.pop3.server proto pop3:
no envelope no dns
localdomains virtual.localdomain1.com virtual.localdomain2.com ...
user yourISPusername is root * here,
password yourISPpassword fetchall
with a hack on your local sendmail.cf like this:
#############################################
# virtual info, local hack for ruleset 98 #
#############################################
# domains to treat as direct mapped local domain
CVvirtual.localdomain1.com virtual.localdomain2.com ...
---------------------------
in ruleset 98 add
-------------------------
# handle virtual users
R$+ <@ $=V . > $: $1 < @ $j . >
R< @ > $+ < @ $=V . > $: $1 < @ $j . >
R< @ > $+ $: $1
R< error : $- $+ > $* $#error $@ $1 $: $2
R< $+ > $+ < @ $+ > $: $>97 $1
This ruleset just strips virtual domain names off the addresses of incoming
mail. Your sendmail must be 8.8 or newer for this to work. Michael says:
I use this scheme with 2 virtual domains and the default ISP user+domain
and service about 30 mail accounts + majordomo on my inside pop3 server
with fetchmail and sendmail 8.83
M7. Multidrop mode isn't parsing envelope addresses from my Received headers as
it should.
It may happen that you're getting what appear to be well-formed sendmail
Received headers, but fetchmail can't seem to extract an envelope address
from them. There can be a couple of reasons for this.
Spurious Received lines need to be skipped:
First, fetchmail might be looking at the wrong Received header. Normally it
looks only on the first one it sees, on the theory that that one was last
added and is going to be the one containing your mailserver's theory of who
the message was addressed to.
Some (unusual) mailserver configurations will generate extra Received lines
which you need to skip. To arrange this, use the optional skip prefix
argument of the 'envelope' option; you may need to say something like
'envelope 1 Received' or 'envelope 2 Received'.
The 'by' clause doesn't contain a mailserver alias:
When fetchmail parses a Received line that looks like
Received: from send103.yahoomail.com (send103.yahoomail.com [205.180.60.92])
by iserv.ttns.net (8.8.5/8.8.5) with SMTP id RAA10088
for <ksturgeon@fbceg.org>; Wed, 9 Sep 1998 17:01:59 -0700
it checks to see if 'iserv.ttns.net' is a DNS alias of your mailserver
before accepting 'ksturgeon@fbceg.org' as an envelope address. This check
might fail if your DNS were misconfigured, or if you were using 'no dns' and
had failed to declare iserv.ttns.net as an alias of your server.
M8. Users are getting multiple copies of messages.
It's a consequence of multidrop. What's happening is that you have N users
subscribed to the same list. The list software sends N copies, not knowing
they will end up in the same multidrop box. Since they are both locally
addressed to all N users, fetchmail delivers N copies to each user.
Fetchmail tries to eliminate adjacent duplicate messages in a multidrop
mailbox. However, this logic depends on the message-ID being identical in
both copies. It also depends on the two copies being adjacent in the server
mailbox. The former is usually the case, but the latter condition sometimes
fails in a timing-dependent way if the server was processing multiple
incoming mail streams.
I could eliminate this problem by keeping a list of all message-IDs received
during a poll so far and dropping any message that matches a seen mail ID.
The trouble is that this is an O(N**2) operation that might significantly
slow down the retrieval of large mail batches.
_________________________________________________________________
Mangled mail
X1. Spurious blank lines are appearing in the headers of fetched mail.
What's probably happening is that the POP/IMAP daemon on your mailserver is
inserting a non-RFC822 header (like X-POP3-Rcpt:) and something in your
delivery path (most likely an old version of the deliver program, which
sendmail often calls to do local delivery) is failing to recognize it as a
header.
This is not fetchmail's problem. The first thing to try is installing a
current version of deliver. If this doesn't work, try to figure out which
other program in your mail path is inserting the blank line and replace
that. If you can't do either of these things, pick a different MDA (such as
maildrop) and declare it with the 'mda' option.
X2. My mail client can't see a Subject line.
First, see X1. This is quite probably the same problem (X-POP3-Rcpt header
or something similar being inserted by the server and choked on by an old
version of deliver).
The O'Reilly sendmail book does warn that IDA sendmail doesn't process X-
headers correctly. If this is your problem, all I can suggest is replacing
IDA sendmail, because it's broken and not RFC822 conformant.
X3. Messages containing "From" at start of line are being split.
If you know the messages aren't split in your server mailbox, then this is a
problem with your POP/IMAP server, your client-side SMTP listener or your
local delivery agent. Fetchmail cannot split messages.
Some POP server daemons ignore Content-Length headers and split messages on
From lines. We have one report that the 2.1 version of the BSD popper
program (as distributed on Solaris 2.5 and elsewhere) is broken this way.
You can test this. Declare an mda of 'cat' and send yourself one piece of
mail containing "From" at start of a line. If you see a split message, your
POP/IMAP server is at fault. Upgrade to a more recent version.
Sendmail and other SMTP listeners don't split RFC822 messages either. What's
probably happening is either sendmail's local delivery agent or your mail
reader are not quite RFC822-conformant and are breaking messages on what it
thinks are Unix-style From headers. You can figure out which by looking at
your client-side mailbox with vi or more. If the message is already split in
your mailbox, your local delivery agent is the problem. If it's not, your
mailreader is the problem.
If you can't replace the offending program, take a look at your sendmail.cf
file. There will likely be a line something like
Mlocal, P=/usr/bin/procmail, F=lsDFMShP, S=10, R=20/40, A=procmail -Y -d $u
describing your local delivery agent. Try inserting the 'E' option in the
flags part (the F= string). This will make sendmail turn each dangerous
start-of-line From into a >From, preventing programs further downstream from
acting up.
X4. My mail is being mangled in a new and different way
The first thing you need to do is pin down what program is doing the
mangling. We don't like getting bug reports about fetchmail that are
actually due to some other program's malfeasance, so please go through this
diagnostic sequence before sending us a complaint.
There are five possible culprits to consider, listed here in the order they
pass your mail:
1. Programs upstream of your server mailbox.
2. The POP or IMAP server on your mailserver host.
3. The fetchmail program itself.
4. Your local sendmail.
5. Your LDA (local delivery agent), as called by sendmail or specified by
mda.
Often it happens that fetchmail itself is OK, but using it exposes
pre-existing bugs in your downstream software, or your downstream software
has a bad interaction with POP/IMAP. You need to pin down exactly where the
message is being garbled in order to deduce what is actually going on.
The first thing to do is send yourself a test message, and retrieve it with
a .fetchmailrc entry containing the following (or by running with the
equivalent command-line options):
mda "cat >MBOX" keep fetchall
This will capture what fetchmail gets from the server, except for (a) the
extra Received header line fetchmail prepends, (b) header address changes
due to rewrite, and (c) any end-of-line changes due to the forcecr and
stripcr options. MBOX will in fact contain what programs downstream of
fetchmail see.
The most common causes of mangling are bugs and misconfigurations in those
downstream programs. If MBOX looks unmangled, you will know that is what is
going on and that it is not fetchmail's problem. Take a look at the other
FAQ items in this section for possible clues about how to fix your problem.
If MBOX looks mangled, the next thing to do is compare it with your actual
server mailbox (if possible). That's why you specified keep, so the server
copy would not be deleted. If your server mailbox looks mangled, programs
upstream of your server mailbox are at fault. Unfortunately there is
probably little you can do about this aside from complaining to your site
postmaster, and nothing at all fetchmail can do about it!
More likely you'll find that the server copy looks OK. In that case either
the POP/IMAP server or fetchmail is doing the mangling. To determine which,
you'll need to telnet to the server port and simulate a fetchmail session
yourself. This is not actually hard (both POP3 and IMAP are simple,
text-only, line-oriented protocols) but requires some attention to detail.
You should be able to use a fetchmail -v log as a model for a session, but
remember that the "*" in your LOGIN or PASS command dump has to be replaced
with your actual password.
The objective of manually simulating fetchmail is so you can see exactly
what fetchmail sees. If you see a mangled message, then your server is at
fault, and you probably need to complain to your mailserver administrators.
However, we like to know what the broken servers are so we can warn people
away from them. So please send us a transcript of the session including the
mangling and the server's initial greeting line. Please tell us anything
else you think might be useful about the server, like the server host's
operating system.
If your manual fetchmail simulation shows an unmangled message,
congratulations. You've found an actual fetchmail bug, which is a pretty
rare thing these days. Complain to us and we'll fix it. Please include the
session transcript of your manual fetchmail simulation along with the other
things described in the FAQ entry on reporting bugs.
X5. Using POP3, retrievals seems to be fetching too much!
This may happen in versions of fetchmail after 4.4.1 and before 4.4.8.
Versions after 4.4.1 use POP3's TOP command rather than RETR, in order to
avoid marking the message seen (leaving it unseen is helpful for later
recovery if you lose your connection in the middle of a retrieval).
Versions of fetchmail from 4.4.2 through 4.4.7 had a bad interaction with
Eudora qpopper versions 2.3 and later. The TOP bounds check was fooled by an
overflow condition in the TOP argument. Decrementing the TOP argument in
4.4.7 fixed this.
Fix: Upgrade to a later version of fetchmail.
Workaround: set the fetchall option. Under POP3 this has the side effect of
forcing RETR use.
X6. My mail attachments are being dropped or mangled.
Fetchmail doesn't discard attachments; fetchmail doesn't have any idea that
attachments are there. Fetchmail treats the body of each message as an
uninterpreted byte stream and passes it through without alteration. If you
are not receiving attachments through fetchmail, it is because your
mailserver is not sending them to you.
The fix for this is to replace your mailserver with one that works. If its
operating system makes this difficult, you should replace its operating
system with one that works. Windows- and NT-based POP servers seem
especially prone to mangle attachments. If you are running one of these,
replacing your server with a Unix machine is probably the only effective
solution.
We've had sporadic reports of problems with Microsoft Exchange and Outlook
servers. These sometimes randomly fail to ship attachments to your client.
This is a known bug, acknowledged by Microsft.
They may also mangle the attachments they do pass through. If you see
unreadable attachments with a ContentType of "application/x-tnef", you're
having this problem. The TNEF utility may help.
The Mail Max POP3 server and the InterChange and Imail IMAP servers are
known to simply drop MIME attachments when uploading messages.
We've also had a report that Lotus Notes sometimes trashes the MIME type of
messages. In particular, it seems to modify MIME headers of type
application/pdf, mangling the type to application/octet-stream. It may
corrupt other MIME types as well.
The IMAP service of Lotus Domino has a known bug in the way it generates
MIME Content-type headers (observed on Lotus Domino 5.0.2b). It's a subtle
one that doesn't show up when Netscape Messenger and other clients use a
FETCH BODY[] to grab the whole message. When fetchmail uses FETCH
RFC822.HEADER and FETCH RFC822.TEXT to get first the header and then the
body, Domino generates different Boundary tags for each part, .e.g. one tag
is declared in the Content-type header and another is used to separate the
MIME parts in the body. This doesn't work. (I have heard a rumor that this
bug is scheduled to be fixed in Domino release 6; you can find a workaround
at contrib/domino.)
Rob Funk explains: Unfortunately there also remain many mail user agents
that don't write correct MIME messages. One big offender is Sun MailTool
attachments, which are formatted enough like MIME that some programs could
get confused; these are generated by the mailtool and dtmail programs (the
mail programs in Sun's OpenWindows and CDE environments).
One solution to problems related to misformatted MIME attachments is the
emil program; see its tutorial file at that site for details on emil. It is
useful for converting character sets, attachment encodings, and attachment
formats. At this writing, emil does not appear to have been maintained since
a patch to version 2.1.0beta9 in late 1997, but it is still useful.
One good way of using emil is from within procmail. You can have procmail
look for signs of problematic message formatting, and pipe those messages
through emil to be fixed. emil will not always be able to fix the problem,
in which case the message is unchanged.
A possible rule to be inserted into a .procmailrc file for using emil would
be:
:0HB
* 1^1 ^Content-Type: \/X-sun[^;]*
* 1^1 ^Content-Type: \/application/mac-binhex[^;]*
* 1^1 ^Content-Transfer-Encoding: \/x-binhex[^;]*
* 1^1 ^Content-Transfer-Encoding: \/x-uuencode[^;]*
{
LOG="Converting $MATCH
"
:0fw
| emil -A B -T Q -B BA -C iso-8859-1 -H Q -F MIME \
| gawk '{gsub(/\r\n?/,"\n");print $0}'
}
The "1^1" in the conditions is a way of specifying to procmail that if any
one of the four listed expressions is found in the message, the total
condition is considered true, and the message gets passed into emil. These
four subconditions check whether the message has a Sun attachment, a binhex
attachment, or a uuencoded attachment; there are others that could be added
to check these things better and to check other relevant conditions. The
"LOG=" line writes a line into the procmail log; the lone double-quote
beginning the following line makes sure the log entry gets an end-of-line
character. The call to gawk (GNU awk) is for fixing end-of-line conventions,
since emil sometimes leaves those in the format of the originating machine;
it could probably be replaced with a sed subsitution.
The emil call itself tries to ensure that the message uses:
* BinHex encoding for any Apple Macintosh-only attachments
* Quoted-Printable encoding for text (when necessary)
* Base64 Encoding for binary attachments
* iso-8859-1 character set for text (unfortunately emil can't yet convert
from windows-1252 to iso-8859-1)
* Quoted-Printable encoding for headers
* MIME attachment format
Most of these (the primary exceptions being the character set and the Apple
binary format) are as they should be for good internet interoperability.
Some mail servers (Lotus Domino is a suspect here) mangle Sun-formatted
messages, so the conversion to MIME needs to happen before such programs see
the message. The ideal is to rid the world of Sun-formatted messages: don't
use mailtool for sending attachments (it doesn't understand MIME anyway, and
most of the world doesn't understand its attachments, so it really shouldn't
be used at all), and make sure dtmail is set to use MIME rather than
mailtool's format.
X7. Some mail attachments are hanging fetchmail.
This isn't fetchmail's problem either; fetchmail doesn't know anything about
mail attachments and doesn't treat them any differently from plain message
data.
The most usual cause of this problem seems to be bugs in your network
transport layer's capability to handle the very large TCP/IP packets that
attachments tend to turn into. You can test this theory by trying to
download the offending message through a webmail account; using HTTP for the
message tends to simulate large-packet stress rather well, and you will
probably find that the messages that seem to be choking fetchmail will make
your HTTP download speed drop to zero.
This problem can be caused by subtle bugs in the packet-reassembly layer of
your TCP/IP stack; these often don't manifest at normal packet sizes. It may
also be caused by malfunctioning path-MTU discovery on the mailserver. Or,
if there's a modem in the link, it may be because the attachment contains
the Hayes mode escape "+++".
X8. A spurious ) is being appended to my messages.
Blame it on that rancid pile of dung and offal called Microsoft Exchange.
Due to the problem described in S2, the IMAP support in fetchmail cannot
follow the IMAP protocol 100%. Most of the time it doesn't matter, but if
you combine it with an SMTP server that behaves unusually, you'll get a
spurious ) at message end.
One piece of software that can trigger this is the Interchange mail server,
as used by, e.g., mailandnews.com. Here's what happens:
1. Someone sends mail to your account. The last line of the message contains
text. So at the SMTP level, the message ends with, e.g. "blahblah\r\n.\r\n"
2. The SMTP handler sees the final "\r\n.\r\n" and recognizes the end of the
message. However, instead of doing the normal thing, which is tossing out
the ".\r\n" and leaving the first '\r\n' as part of the email body,
Interchange throws out the whole "\r\n.\r\n", and leaves the email body
without any line terminator at the end of it. RFC821 does not forbid this,
though it probably should.
3. Fetchmail, or some other IMAP client, asks for the message. IMAP returns
it, but it's enclosed inside parentheses, according to the protocol. The
message size in bytes is also present. Because the message doesn't end with
a line terminator, the IMAP client sees:
....blahblah)...
where the ')' is from IMAP.
4. Fetchmail only deals with complete lines, and can't trust the stated
message size because Microsoft Exchange fscks it up.
5. As a result, fetchmail takes the final 'blahblah)' and puts it at the end
of the message it forwards on. If you have verbosity on, you'll get a
message about actual != expected.
There is no fix for this. The nuke mentioned in S2 looks more tempting all
the time.
X9. Missing "Content-Transfer-Encoding" header with Domino IMAP
Domino 6 IMAP was found by Anthony Kim in February 2006 to erroneously omit
the "Content-Transfer-Encoding" header in messages downloaded through IMAP,
causing messages to display improperly. This happened with Domino's incoming
mail format configured to "Prefers MIME". Solution: switch Domino to "Keep
in Sender's format".
Reference: Anthony Kim's list post
_________________________________________________________________
Other problems
O1. The --logfile option doesn't work if the logfile doesn't exist.
This is a feature, not a bug. It's in line with normal practice for system
daemons and allows you to suppress logging by removing the log, without
hacking potentially fragile startup scripts. To get around it, just touch(1)
the logfile before you run fetchmail (this will have no effect on the
contents of the logfile if it already exists).
O2. Every time I get a POP or IMAP message the header is dumped to all my
terminal sessions.
Fetchmail uses the local sendmail to perform final delivery, which Netscape
and other clients doesn't do; the announcement of new messages is done by a
daemon that sendmail pokes. There should be a "biff" command to control
this. Type
biff n
to turn it off. If this doesn't work, try the command
chmod -x $(tty)
which is essentially what biff -n will do. If this doesn't work, comment out
any reference to "comsat" in your /etc/inetd.conf file and restart inetd.
In Slackware Linux distributions, the last line in /etc/profile is
biff y
Change this to
biff n
to solve the problem system-wide.
O3. Does fetchmail reread its rc file every poll cycle?
No, but versions 5.2.2 and later will notice when you modify your rc file
and restart, reading it.
O4. Why do deleted messages show up again when I take a line hit while
downloading?
Because you're using a POP3 other than Qualcomm qpopper, or an IMAP with a
long expunge interval.
According to the POP3 RFCs, deletes aren't actually performed until you
issue the end-of-session QUIT command. Fetchmail cannot fix this, because
doing it right takes cooperation from the server. There are two possible
remedies:
One is to switch to qpopper (the free POP3 server from Qualcomm, the Eudora
people). The qpopper software violates the POP3 RFCs by doing an expunge
(removing deleted messages) on a line hangup, as well as on processing a
QUIT command.
The other (which we recommend) is to switch to IMAP. IMAP has an explicit
expunge command and fetchmail normally uses it to delete messages
immediately after they are downloaded.
If you get very unlucky, you might take a line hit in the window between the
delete and the expunge. If you've set a longer expunge interval, the window
gets wider. This problem should correct itself the next time you complete a
successful query.
O5. Why is fetched mail being logged with my name, not the real From address?
Because logging is done based on the address indicated by the sending SMTP's
MAIL FROM, and some listeners are picky about that address.
Some SMTP listeners get upset if you try to hand them a MAIL FROM address
naming a different host than the originating site for your connection. This
is a feature, not a bug -- it's supposed to help prevent people from forging
mail with a bogus origin site. (RFC 1123 says you shouldn't do this
exclusion...)
Since the originating site of a fetchmail delivery connection is localhost,
this effectively means these picky listeners will barf on any MAIL FROM
address fetchmail hands them with an @ in it!
Versions 2.1 and up try the header From address first and fall back to the
calling-user ID. So if your SMTP listener isn't picky, the log will look
right.
O6. I'm seeing long sendmail delays or hangs near the start of each poll cycle.
Sendmail does a hostname lookup when it first starts up, and also each time
it gets a HELO in listener mode.
Your resolver configuration may be causing one of these lookups to fail and
time out. Check /etc/resolv.conf and /etc/hosts file. Make sure your
hostname and fully-qualified domain name are both in /etc/hosts, and that
hosts is looked at before DNS is queried. You probably also want your remote
mail server(s) to be in the hosts file.
You can suppress the startup-time lookup if need to by reconfiguring with
FEATURE(nodns).
Configuring your bind library to cache DNS lookups locally may help, and is
a good idea for speeding up other services as well. Switching to a faster
MTA like qmail or exim might help.
O7. Why doesn't fetchmail deliver mail in date-sorted order?
Because that's not the order the server hands it to fetchmail in.
Fetchmail getting mail from a POP server delivers mail in the order that
your server delivers mail. Fetchmail can't do anything about this; it's a
limitation of the underlying POP protocol.
In theory it might be possible for fetchmail in IMAP mode to sort messages
by date, but this would be in violation of two basics of fetchmail's design
philosophy: (a) to be as simple and transparent a pipe as possible, and (b)
to hide, rather than emphasize, the differences between the remote-fetch
protocols it uses.
Re-ordering messages is a user-agent function, anyway.
O8. I'm using pppd. Why isn't my monitor option working?
There is a combination of circumstances that can confuse fetchmail. If you
have set up demand dialing with pppd, and pppd has an idle timeout, and you
have lcp-echo-interval set, then the lcp-echo-interval time must be longer
than the pppd idle timeout. Otherwise it is going keep increasing the packet
counters that fetchmail relies upon, triggering fetchmail into polling after
its own delay interval and thus preventing the pppd link from ever reaching
its inactivity timeout.
O9. Why does fetchmail keep retrieving the same messages over and over?
First, check to see that you haven't enabled the keep and fetchall option.
If you have, turn keep off.
There are various forms of lossage involving the POP3 UIDL feature that can
lead to all your old messages being seen again after a line drop. I have
given up trying to fix these, as the UIDL code breaks worse every time I
touch it. The problem is fundamental; maintaining and garbage-collecting the
right kind of client-side state is just hard. Whoever put UIDLs in RFC1725
and removed LAST should be hung up by his thumbs and whipped with scorpions.
The right answers are either (a) live with the occasional breakage, (b)
switch to IMAP4, or (c) fix the code yourself and send me a patch. Unless
you choose (c), I don't want to hear about it.
This can also happen when some other mail client is logged in to your mail
server, if it uses a simple exclusive-locking scheme (and many, especially
most POP3 servers, do exactly that). Your fetchmail is able to retrieve the
messages, but because the mailbox is write-locked by the other instance
yours can neither mark messages seen or delete them. The solution is to
either (a) wait for the other client to finish, or (b) terminate it.
James Stevens <James.Stevens at kyzo.com> writes:
We had a Linux box dialing the Net and collecting mail from an NT POP3
server. Fetchmail was correctly collecting and deleting each e-mail one by
one. However,the dial-up connection was very unreliable and would often just
drop out in the middle of a session.
Interestingly, unless the TCP POP3 connection was terminated normally (I
guess with a POP3 "QUIT" command) NT would then roll back all the deletes
!!!
This meant if the first e-mail was very large it might just end up
continuously collecting it, basically jamming the queue. Or, if the queue
became very full itmight never get a long enough phone connection to
retrieve the entire mailbox, and NT would roll back any deletes, so it would
end up collecting (and delivering) the first few e-mails again and again. As
the POP3 mailbox became fuller and fuller the chances of getting a
connection long enough to collect theentire mailbox became smaller and
smaller.
Our solution was to make fetchmail only collect a few (say 5 or 10) e-mails
at atime, thus trying to ensure that the POP3 connection is terminated
correctly.
Unfortunately, this is exactly the way POP3 servers are supposed to behave
on a line drop, according to the RFCs. I recommend switching to IMAP and
using a short expunge interval.
O10. Why is the received date on all my messages the same?
This is a design choice in your MTA, not fetchmail. It's taking the received
date from the last Received header.
O11. I keep getting messages that say "Repoll immediately" in my logs.
This is your server barfing on the CAPA probe that fetchmail sends.
If you run fetchmail in daemon mode (say "set daemon 600"), you will get the
message only once per run.
If you set an authentication method explicitly (say, with auth password),
you will never get the message.
O12. Fetchmail no longer expunges mail on a 451 SMTP response.
This is a feature, not a bug.
Any 4xx response (like 451) indicates a transient (temporary) error. This
means that the mail could be accepted if retried later. Lookup failures are
normally transient errors as a mail should not get rejected if a dns server
is unreachable or down.
A permanent reject response is of the form 5xx (like 550).
You could tell your SMTP server to not lookup any addresses if you are not
keen on checking the sender addresses. This problem typically occurs if your
mail server is not checking the sender addresses, but your local server is.
Or you could declare antispam 451.
Or, you could check your nameserver configuration and query logs for dns
errors.
All these issues are not related to fetchmail directly.
O13. I want timestamp information in my fetchmail logs.
Write a preconnect command in your configuration file that does something
like "date >> $HOME/Procmail/fetchmail.log".
O14. Fetchmail no longer deletes oversized mails with --flush.
Use --limitflush (available since release 6.3.0) to delete oversized mails
along with the --limit option. If you are already having flush in your
rcfile to delete oversized mails, replace it with limitflush to avoid losing
mails unintentionally.
The --flush option is primarily designed to delete mails which have been
read/downloaded but not deleted yet. This option cannot be overloaded to
delete oversized mails as it cannot be guessed whether the user wants to
delete only read/downloaded mails or only oversized mails or both when a
user specifies both --limit and --flush. Hence, a separate --limitflush has
been added to resolve the ambiguity.
O15. Fetchmail always retains the first message in the mailbox.
This happens when fetchmail sees an "X-IMAP:" header in the very first
message in your mailbox. This usually stems from a message like the one
shown below, which is automatically created on your server. This message
shows up if the University of Washington IMAP or PINE software is used on
the server together with a POP2 or POP3 daemon that is not aware of these
messages, such as some versions of Qualcomm Popper (QPOP):
From MAILER-DAEMON Wed Nov 23 11:38:42 2005
Date: 23 Nov 2005 11:38:42 +0100
From: Mail System Internal Data <MAILER-DAEMON@imap.example.org>
Subject: DON'T DELETE THIS MESSAGE -- FOLDER INTERNAL DATA
Message-ID: <1132742322@imap.example.org>
X-IMAP: 1132742306 0000000001
Status: RO
This text is part of the internal format of your mail folder, and is not
a real message. It is created automatically by the mail system software.
If deleted, important folder data will be lost, and it will be re-created
with the data reset to initial values.
As this message does not contain useful information, fetchmail is not
retrieving it. And deleting it might slow down the server if you are keeping
messages on the server, and the server would recreate it anyways, that's why
fetchmail does not bother to delete it either.
O16. Why is the Fetchmail FAQ only available in ISO-216 A4 format? How do I get
the FAQ in Letter format?
All the world uses ISO-216:1975 "A4" paper except for North America. Using
A4 format reaches far more people than (formerly known as DIN A4, from
DIN 476) format. Besides that, A4 paper is available in North America. For
further information on the Letter-vs-A4 story, see:
* Markus Kuhn: "International standard paper sizes"
* Brian Forte: "A4 vs US Letter"
Offering the document formatted for two different paper sizes would bloat
the package beyond reason, and formatting in a way that fits A4 and Letter
paper formats would be a waste of paper in most parts of the world. For that
reason, fetchmail only ships with an A4 formatted PDF document.
To create a letter-sized PDF, install HTMLDOC, edit fetchmail-FAQ.book in
the source directory with your favorite text editor, replace --size A4 by
--size letter, and type:
make fetchmail-FAQ.pdf
_________________________________________________________________
Eric S. Raymond <esr@thyrsus.com>
Matthias Andree