.TH VIRTUAL 5 .ad .fi .SH NAME virtual \- format of Postfix virtual alias table .SH SYNOPSIS .na .nf \fBpostmap /etc/postfix/virtual\fR \fBpostmap -q "\fIstring\fB" /etc/postfix/virtual\fR \fBpostmap -q - /etc/postfix/virtual <\fIinputfile\fR .SH DESCRIPTION .ad .fi The optional \fBvirtual\fR alias table specifies address aliasing for arbitrary local or non-local recipient addresses. Virtual aliasing is recursive, and is done by the Postfix \fBcleanup\fR(8) daemon. The main applications of virtual aliasing are: .IP \(bu To redirect mail for one address to one or more addresses. .IP \(bu To implement virtual alias domains where all addresses are aliased to addresses in other domains. .sp Virtual alias domains are not to be confused with the virtual mailbox domains that are implemented with the Postfix \fBvirtual\fR(8) mail delivery agent. With virtual mailbox domains, each recipient address can have its own mailbox. .PP Virtual aliasing is applied only to recipient envelope addresses, and does not affect message headers. Think Sendmail rule set \fBS0\fR, if you like. Use \fBcanonical\fR(5) mapping to rewrite header and envelope addresses in general. Normally, the \fBvirtual\fR alias table is specified as a text file that serves as input to the \fBpostmap\fR(1) command. The result, an indexed file in \fBdbm\fR or \fBdb\fR format, is used for fast searching by the mail system. Execute the command \fBpostmap /etc/postfix/virtual\fR in order to rebuild the indexed file after changing the text file. When the table is provided via other means such as NIS, LDAP or SQL, the same lookups are done as for ordinary indexed files. Alternatively, the table can be provided as a regular-expression map where patterns are given as regular expressions. In that case, the lookups are done in a slightly different way as described below. .SH TABLE FORMAT .na .nf .ad .fi The format of the virtual table is as follows, mappings being tried in the order as listed in this manual page: .IP "\fIpattern result\fR" When \fIpattern\fR matches a mail address, replace it by the corresponding \fIresult\fR. .IP "blank lines and comments" Empty lines and whitespace-only lines are ignored, as are lines whose first non-whitespace character is a `#'. .IP "multi-line text" A logical line starts with non-whitespace text. A line that starts with whitespace continues a logical line. .PP With lookups from indexed files such as DB or DBM, or from networked tables such as NIS, LDAP or SQL, patterns are tried in the order as listed below: .IP "\fIuser\fR@\fIdomain address, address, ...\fR" Mail for \fIuser\fR@\fIdomain\fR is redirected to \fIaddress\fR. This form has the highest precedence. .IP "\fIuser address, address, ...\fR" Mail for \fIuser\fR@\fIsite\fR is redirected to \fIaddress\fR when \fIsite\fR is equal to $\fBmyorigin\fR, when \fIsite\fR is listed in $\fRmydestination\fR, or when it is listed in $\fIinet_interfaces\fR. .sp This functionality overlaps with functionality of the local \fIaliases\fR(5) database. The difference is that \fBvirtual\fR mapping can be applied to non-local addresses. .IP "@\fIdomain address, address, ...\fR" Mail for any user in \fIdomain\fR is redirected to \fIaddress\fR. This form has the lowest precedence. .PP In all the above forms, when \fIaddress\fR has the form @\fIotherdomain\fR, the result is the same user in \fIotherdomain\fR. This works for the first address in the expansion only. .SH ADDRESS EXTENSION .na .nf .fi .ad When a mail address localpart contains the optional recipient delimiter (e.g., \fIuser+foo\fR@\fIdomain\fR), the lookup order becomes: \fIuser+foo\fR@\fIdomain\fR, \fIuser\fR@\fIdomain\fR, \fIuser+foo\fR, \fIuser\fR, and @\fIdomain\fR. An unmatched address extension (\fI+foo\fR) is propagated to the result of table lookup. .SH VIRTUAL ALIAS DOMAINS .na .nf .ad .fi Besides virtual aliases, the virtual alias table can also be used to implement virtual alias domains. With a virtual alias domain, all recipient addresses are aliased to addresses in other domains. Virtual alias domains are not to be confused with the virtual mailbox domains that are implemented with the Postfix \fBvirtual\fR(8) mail delivery agent. With virtual mailbox domains, each recipient address can have its own mailbox. With a virtual alias domain, the virtual domain has its own user name space. Local (i.e. non-virtual) usernames are not visible in a virtual alias domain. In particular, local \fBaliases\fR(5) and local mailing lists are not visible as \fIlocalname@virtual-alias.domain\fR. Support for a virtual alias domain looks like: /etc/postfix/main.cf: .in +4 virtual_alias_maps = hash:/etc/postfix/virtual Note: some systems use \fBdbm\fR databases instead of \fBhash\fR. See the output from \fBpostconf -m\fR for available database types. .ti -4 /etc/postfix/virtual: .nf .na \fIvirtual-alias.domain anything\fR (right-hand content does not matter) \fIpostmaster@virtual-alias.domain postmaster\fR \fIuser1@virtual-alias.domain address1\fR \fIuser2@virtual-alias.domain address2, address3\fR .fi .in -4 .ad .fi .sp The \fIvirtual-alias.domain anything\fR entry is required for a virtual alias domain. \fBWithout this entry, mail is rejected with "relay access denied", or bounces with "mail loops back to myself".\fR Do not specify virtual alias domain names in the \fBmain.cf mydestination\fR or \fBrelay_domains\fR configuration parameters. With a virtual alias domain, the Postfix SMTP server accepts mail for \fIknown-user@virtual-alias.domain\fR, and rejects mail for \fIunknown-user\fR@\fIvirtual-alias.domain\fR as undeliverable. Instead of specifying the virtual alias domain name via the \fBvirtual_alias_maps\fR table, you may also specify it via the \fBmain.cf virtual_alias_domains\fR configuration parameter. This latter parameter uses the same syntax as the \fBmain.cf mydestination\fR configuration parameter. .SH REGULAR EXPRESSION TABLES .na .nf .ad .fi This section describes how the table lookups change when the table is given in the form of regular expressions. For a description of regular expression lookup table syntax, see \fBregexp_table\fR(5) or \fBpcre_table\fR(5). Each pattern is a regular expression that is applied to the entire address being looked up. Thus, \fIuser@domain\fR mail addresses are not broken up into their \fIuser\fR and \fI@domain\fR constituent parts, nor is \fIuser+foo\fR broken up into \fIuser\fR and \fIfoo\fR. Patterns are applied in the order as specified in the table, until a pattern is found that matches the search string. Results are the same as with indexed file lookups, with the additional feature that parenthesized substrings from the pattern can be interpolated as \fB$1\fR, \fB$2\fR and so on. .SH BUGS .ad .fi The table format does not understand quoting conventions. .SH CONFIGURATION PARAMETERS .na .nf .ad .fi The following \fBmain.cf\fR parameters are especially relevant to this topic. See the Postfix \fBmain.cf\fR file for syntax details and for default values. Use the \fBpostfix reload\fR command after a configuration change. .IP \fBvirtual_alias_maps\fR List of virtual aliasing tables. .IP \fBvirtual_alias_domains\fR List of virtual alias domains. This uses the same syntax as the \fBmydestination\fR parameter. .PP Other parameters of interest: .IP \fBinet_interfaces\fR The network interface addresses that this system receives mail on. You need to stop and start Postfix when this parameter changes. .IP \fBmydestination\fR List of domains that this mail system considers local. .IP \fBmyorigin\fR The domain that is appended to any address that does not have a domain. .IP \fBowner_request_special\fR Give special treatment to \fBowner-\fIxxx\fR and \fIxxx\fB-request\fR addresses. .SH SEE ALSO .na .nf cleanup(8) canonicalize and enqueue mail postmap(1) create mapping table regexp_table(5) POSIX regular expression table format pcre_table(5) Perl Compatible Regular Expression table format .SH LICENSE .na .nf .ad .fi The Secure Mailer license must be distributed with this software. .SH AUTHOR(S) .na .nf Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA