<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> <title> Postfix manual - pipe(8) </title> </head> <body> <pre> PIPE(8) PIPE(8) <b>NAME</b> pipe - Postfix delivery to external command <b>SYNOPSIS</b> <b>pipe</b> [generic Postfix daemon options] command_attributes... <b>DESCRIPTION</b> The <a href="pipe.8.html"><b>pipe</b>(8)</a> daemon processes requests from the Postfix queue manager to deliver messages to external commands. This program expects to be run from the <a href="master.8.html"><b>master</b>(8)</a> process manager. Message attributes such as sender address, recipient address and next-hop host name can be specified as com- mand-line macros that are expanded before the external command is executed. The <a href="pipe.8.html"><b>pipe</b>(8)</a> daemon updates queue files and marks recipi- ents as finished, or it informs the queue manager that delivery should be tried again at a later time. Delivery status reports are sent to the <a href="bounce.8.html"><b>bounce</b>(8)</a>, <a href="defer.8.html"><b>defer</b>(8)</a> or <a href="trace.8.html"><b>trace</b>(8)</a> daemon as appropriate. <b>SINGLE-RECIPIENT DELIVERY</b> Some external commands cannot handle more than one recipi- ent per delivery request. Examples of such transports are pagers or fax machines. To prevent Postfix from sending multiple recipients per delivery request, specify <i>transport</i><b>_destination_recipient_limit = 1</b> in the Postfix <a href="postconf.5.html"><b>main.cf</b></a> file, where <i>transport</i> is the name in the first column of the Postfix <a href="master.5.html"><b>master.cf</b></a> entry for the pipe-based delivery transport. <b>COMMAND ATTRIBUTE SYNTAX</b> The external command attributes are given in the <a href="master.5.html"><b>master.cf</b></a> file at the end of a service definition. The syntax is as follows: <b>chroot=</b><i>pathname</i> (optional) Change the process root directory and working directory to the named directory. This happens before switching to the privileges specified with the <b>user</b> attribute, and before executing the optional <b>directory=</b><i>pathname</i> directive. Delivery is deferred in case of failure. This feature is available as of Postfix 2.3. <b>directory=</b><i>pathname</i> (optional) Change to the named directory before executing the external command. The directory must be accessible for the user specified with the <b>user</b> attribute (see below). The default working directory is <b>$<a href="postconf.5.html#queue_directory">queue_directory</a></b>. Delivery is deferred in case of failure. This feature is available as of Postfix 2.2. <b>eol=</b><i>string</i> (optional, default: <b>\n</b>) The output record delimiter. Typically one would use either <b>\r\n</b> or <b>\n</b>. The usual C-style backslash escape sequences are recognized: <b>\a \b \f \n \r \t</b> <b>\v \</b><i>ddd</i> (up to three octal digits) and <b>\\</b>. <b>flags=BDFORhqu.</b>> (optional) Optional message processing flags. By default, a message is copied unchanged. <b>B</b> Append a blank line at the end of each mes- sage. This is required by some mail user agents that recognize "<b>From</b> " lines only when preceded by a blank line. <b>D</b> Prepend a "<b>Delivered-To:</b> <i>recipient</i>" message header with the envelope recipient address. Note: for this to work, the <i>transport</i><b>_desti-</b> <b>nation_recipient_limit</b> must be 1. This feature is available as of Postfix 2.0. <b>F</b> Prepend a "<b>From</b> <i>sender time</i><b>_</b><i>stamp</i>" envelope header to the message content. This is expected by, for example, <b>UUCP</b> software. <b>O</b> Prepend an "<b>X-Original-To:</b> <i>recipient</i>" mes- sage header with the recipient address as given to Postfix. Note: for this to work, the <i>transport</i><b>_destination_recipient_limit</b> must be 1. This feature is available as of Postfix 2.0. <b>R</b> Prepend a <b>Return-Path:</b> message header with the envelope sender address. <b>h</b> Fold the command-line <b>$recipient</b> domain name and <b>$nexthop</b> host name to lower case. This is recommended for delivery via <b>UUCP</b>. <b>q</b> Quote white space and other special charac- ters in the command-line <b>$sender</b> and <b>$recip-</b> <b>ient</b> address localparts (text to the left of the right-most <b>@</b> character), according to an 8-bit transparent version of <a href="http://www.faqs.org/rfcs/rfc822.html">RFC 822</a>. This is recommended for delivery via <b>UUCP</b> or <b>BSMTP</b>. The result is compatible with the address parsing of command-line recipients by the Postfix <a href="sendmail.1.html"><b>sendmail</b>(1)</a> mail submission command. The <b>q</b> flag affects only entire addresses, not the partial address information from the <b>$user</b>, <b>$extension</b> or <b>$mailbox</b> command-line macros. <b>u</b> Fold the command-line <b>$recipient</b> address localpart (text to the left of the right- most <b>@</b> character) to lower case. This is recommended for delivery via <b>UUCP</b>. <b>.</b> Prepend "<b>.</b>" to lines starting with "<b>.</b>". This is needed by, for example, <b>BSMTP</b> software. > Prepend ">" to lines starting with "<b>From</b> ". This is expected by, for example, <b>UUCP</b> soft- ware. <b>null_sender</b>=<i>replacement</i> (default: MAILER-DAEMON) Replace the null sender address (typically used for delivery status notifications) with the specified text when expanding the <b>$sender</b> command-line macro, and when generating a From_ or Return-Path: message header. If the null sender replacement text is a non-empty string then it is affected by the <b>q</b> flag for address quoting in command-line arguments. The null sender replacement text may be empty; this form is recommended for content filters that feed mail back into Postfix. The empty sender address is not affected by the <b>q</b> flag for address quoting in command-line arguments. Caution: a null sender address is easily mis-parsed by naive software. For example, when the <a href="pipe.8.html"><b>pipe</b>(8)</a> daemon executes a command such as: command -f$sender -- $recipient (<i>bad</i>) the command will mis-parse the -f option value when the sender address is a null string. For correct parsing, specify <b>$sender</b> as an argument by itself: command -f $sender -- $recipient (<i>good</i>) This feature is available with Postfix 2.3 and later. <b>size</b>=<i>size</i><b>_</b><i>limit</i> (optional) Messages greater in size than this limit (in bytes) will be returned to the sender as undeliverable. <b>user</b>=<i>username</i> (required) <b>user</b>=<i>username</i>:<i>groupname</i> Execute the external command with the rights of the specified <i>username</i>. The software refuses to exe- cute commands with root privileges, or with the privileges of the mail system owner. If <i>groupname</i> is specified, the corresponding group ID is used instead of the group ID of <i>username</i>. <b>argv</b>=<i>command</i>... (required) The command to be executed. This must be specified as the last command attribute. The command is exe- cuted directly, i.e. without interpretation of shell meta characters by a shell command inter- preter. In the command argument vector, the following macros are recognized and replaced with correspond- ing information from the Postfix queue manager delivery request. In addition to the form ${<i>name</i>}, the forms $<i>name</i> and $(<i>name</i>) are also recognized. Specify <b>$$</b> where a single <b>$</b> is wanted. <b>${client_address</b>} This macro expands to the remote client net- work address. This is available in Postfix 2.2 and later. <b>${client_helo</b>} This macro expands to the remote client HELO command parameter. This is available in Postfix 2.2 and later. <b>${client_hostname</b>} This macro expands to the remote client hostname. This is available in Postfix 2.2 and later. <b>${client_protocol</b>} This macro expands to the remote client pro- tocol. This is available in Postfix 2.2 and later. <b>${extension</b>} This macro expands to the extension part of a recipient address. For example, with an address <i>user+foo@domain</i> the extension is <i>foo</i>. A command-line argument that contains <b>${extension</b>} expands into as many command- line arguments as there are recipients. This information is modified by the <b>u</b> flag for case folding. <b>${mailbox</b>} This macro expands to the complete local part of a recipient address. For example, with an address <i>user+foo@domain</i> the mailbox is <i>user+foo</i>. A command-line argument that contains <b>${mailbox</b>} expands to as many command-line arguments as there are recipients. This information is modified by the <b>u</b> flag for case folding. <b>${nexthop</b>} This macro expands to the next-hop hostname. This information is modified by the <b>h</b> flag for case folding. <b>${recipient</b>} This macro expands to the complete recipient address. A command-line argument that contains <b>${recipient</b>} expands to as many command-line arguments as there are recipients. This information is modified by the <b>hqu</b> flags for quoting and case folding. <b>${sasl_method</b>} This macro expands to the SASL authentica- tion mechanism used during the reception of the message. An empty string is passed if the message has been received without SASL authentication. This is available in Postfix 2.2 and later. <b>${sasl_sender</b>} This macro expands to the SASL sender name (i.e. the original submitter as per <a href="http://www.faqs.org/rfcs/rfc2554.html">RFC</a> <a href="http://www.faqs.org/rfcs/rfc2554.html">2554</a>) used during the reception of the mes- sage. This is available in Postfix 2.2 and later. <b>${sasl_username</b>} This macro expands to the SASL user name used during the reception of the message. An empty string is passed if the message has been received without SASL authentication. This is available in Postfix 2.2 and later. <b>${sender</b>} This macro expands to the envelope sender address. By default, the null sender address expands to MAILER-DAEMON; this can be changed with the <b>null_sender</b> attribute, as described above. This information is modified by the <b>q</b> flag for quoting. <b>${size</b>} This macro expands to Postfix's idea of the message size, which is an approximation of the size of the message as delivered. <b>${user</b>} This macro expands to the username part of a recipient address. For example, with an address <i>user+foo@domain</i> the username part is <i>user</i>. A command-line argument that contains <b>${user</b>} expands into as many command-line arguments as there are recipients. This information is modified by the <b>u</b> flag for case folding. <b>STANDARDS</b> <a href="http://www.faqs.org/rfcs/rfc3463.html">RFC 3463</a> (Enhanced status codes) <b>DIAGNOSTICS</b> Command exit status codes are expected to follow the con- ventions defined in <<b>sysexits.h</b>>. Exit status 0 means normal successful completion. Postfix version 2.3 and later support <a href="http://www.faqs.org/rfcs/rfc3463.html">RFC 3463</a>-style enhanced status codes. If a command terminates with a non-zero exit status, and the command output begins with an enhanced status code, this status code takes precedence over the non-zero exit status. Problems and transactions are logged to <b>syslogd</b>(8). Cor- rupted message files are marked so that the queue manager can move them to the <b>corrupt</b> queue for further inspection. <b>SECURITY</b> This program needs a dual personality 1) to access the private Postfix queue and IPC mechanisms, and 2) to exe- cute external commands as the specified user. It is there- fore security sensitive. <b>CONFIGURATION PARAMETERS</b> Changes to <a href="postconf.5.html"><b>main.cf</b></a> are picked up automatically as <a href="pipe.8.html"><b>pipe</b>(8)</a> processes run for only a limited amount of time. Use the command "<b>postfix reload</b>" to speed up a change. The text below provides only a parameter summary. See <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples. <b>RESOURCE AND RATE CONTROLS</b> In the text below, <i>transport</i> is the first field in a <b>mas-</b> <b>ter.cf</b> entry. <i>transport</i><b>_destination_concurrency_limit ($<a href="postconf.5.html#default_destination_concurrency_limit">default_destina</a>-</b> <b><a href="postconf.5.html#default_destination_concurrency_limit">tion_concurrency_limit</a>)</b> Limit the number of parallel deliveries to the same destination, for delivery via the named <i>transport</i>. The limit is enforced by the Postfix queue manager. <i>transport</i><b>_destination_recipient_limit ($<a href="postconf.5.html#default_destination_recipient_limit">default_destina</a>-</b> <b><a href="postconf.5.html#default_destination_recipient_limit">tion_recipient_limit</a>)</b> Limit the number of recipients per message deliv- ery, for delivery via the named <i>transport</i>. The limit is enforced by the Postfix queue manager. <i>transport</i><b>_time_limit ($<a href="postconf.5.html#command_time_limit">command_time_limit</a>)</b> Limit the time for delivery to external command, for delivery via the named <i>transport</i>. The limit is enforced by the pipe delivery agent. Postfix 2.4 and later support a suffix that speci- fies the time unit: s (seconds), m (minutes), h (hours), d (days), w (weeks). The default time unit is seconds. <b>MISCELLANEOUS CONTROLS</b> <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b> The default location of the Postfix <a href="postconf.5.html">main.cf</a> and <a href="master.5.html">master.cf</a> configuration files. <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b> How much time a Postfix daemon process may take to handle a request before it is terminated by a built-in watchdog timer. <b><a href="postconf.5.html#delay_logging_resolution_limit">delay_logging_resolution_limit</a> (2)</b> The maximal number of digits after the decimal point when logging sub-second delay values. <b><a href="postconf.5.html#export_environment">export_environment</a> (see 'postconf -d' output)</b> The list of environment variables that a Postfix process will export to non-Postfix processes. <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b> The time limit for sending or receiving information over an internal communication channel. <b><a href="postconf.5.html#mail_owner">mail_owner</a> (postfix)</b> The UNIX system account that owns the Postfix queue and most Postfix daemon processes. <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b> The maximum amount of time that an idle Postfix daemon process waits for an incoming connection before terminating voluntarily. <b><a href="postconf.5.html#max_use">max_use</a> (100)</b> The maximal number of incoming connections that a Postfix daemon process will service before termi- nating voluntarily. <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b> The process ID of a Postfix command or daemon process. <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b> The process name of a Postfix command or daemon process. <b><a href="postconf.5.html#queue_directory">queue_directory</a> (see 'postconf -d' output)</b> The location of the Postfix top-level queue direc- tory. <b><a href="postconf.5.html#recipient_delimiter">recipient_delimiter</a> (empty)</b> The separator between user names and address exten- sions (user+foo). <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b> The syslog facility of Postfix logging. <b><a href="postconf.5.html#syslog_name">syslog_name</a> (postfix)</b> The mail system name that is prepended to the process name in syslog records, so that "smtpd" becomes, for example, "postfix/smtpd". <b>SEE ALSO</b> <a href="qmgr.8.html">qmgr(8)</a>, queue manager <a href="bounce.8.html">bounce(8)</a>, delivery status reports <a href="postconf.5.html">postconf(5)</a>, configuration parameters <a href="master.5.html">master(5)</a>, generic daemon options <a href="master.8.html">master(8)</a>, process manager syslogd(8), system logging <b>LICENSE</b> The Secure Mailer license must be distributed with this software. <b>AUTHOR(S)</b> Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA PIPE(8) </pre> </body> </html>