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diff --git a/html/MAILLOG_README.html b/html/MAILLOG_README.html new file mode 100644 index 0000000..aa371ba --- /dev/null +++ b/html/MAILLOG_README.html @@ -0,0 +1,183 @@ +<!doctype html public "-//W3C//DTD HTML 4.01 Transitional//EN" + "http://www.w3.org/TR/html4/loose.dtd"> + +<html> + +<head> + +<title>Postfix logging to file or stdout</title> + +<meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> + +</head> + +<body> + +<h1><img src="postfix-logo.jpg" width="203" height="98" ALT="">Postfix +logging to file or stdout</h1> + +<hr> + +<h2>Overview </h2> + +<p> Postfix supports it own logging system as an alternative to +syslog (which remains the default). This is available with Postfix +version 3.4 or later. </p> + +<p> Topics covered in this document: </p> + +<ul> + +<li><a href="#log-to-file">Configuring logging to file</a> + +<li><a href="#log-to-stdout">Configuring logging to stdout</a> + +<li><a href="#logrotate">Rotating logs </a> + +<li><a href="#limitations">Limitations</a> + +</ul> + +<h2> <a name="log-to-file"> Configuring logging to file </a> </h2> + +<p> Logging to file solves a usability problem for MacOS, and +eliminates multiple problems for systemd-based systems. </p> + +<ol> + +<li> <p> Add the following line to <a href="master.5.html">master.cf</a> if not already present +(note: there must be no whitespace at the start of the line): </p> + +<blockquote> +<pre> +postlog unix-dgram n - n - 1 postlogd +</pre> +</blockquote> + +<p> Note: the service type "<b>unix-dgram</b>" was introduced with +Postfix 3.4. Remove the above line before backing out to an older +Postfix version. </p> + +<li> <p> Configure Postfix to write logging, to, for example, +/var/log/postfix.log. See also the "<a href="#logrotate">Logfile +rotation</a>" section below for logfile management. </p> + +<blockquote> +<pre> +# postfix stop +# postconf <a href="postconf.5.html#maillog_file">maillog_file</a>=/var/log/postfix.log +# postfix start +</pre> +</blockquote> + +<p> By default, the logfile name must start with "/var" or "/dev/stdout" +(the list of allowed prefixes is configured with the <a href="postconf.5.html#maillog_file_prefixes">maillog_file_prefixes</a> +parameter). This safety mechanism limits the damage from a single +configuration mistake. </p> + +</ol> + +<h2> <a name="log-to-stdout"> Configuring logging to stdout </a> </h2> + +<p> Logging to stdout is useful when Postfix runs in a container, +as it eliminates a syslogd dependency. </p> + +<ol> + +<li> <p> Add the following line to <a href="master.5.html">master.cf</a> if not already present (note: +there must be no whitespace at the start of the line): </p> + +<blockquote> +<pre> +postlog unix-dgram n - n - 1 postlogd +</pre> +</blockquote> + +<p> Note: the service type "<b>unix-dgram</b>" was introduced with +Postfix 3.4. Remove the above line before backing out to an older +Postfix version. </p> + +<li> <p> Configure <a href="postconf.5.html">main.cf</a> with "<a href="postconf.5.html#maillog_file">maillog_file</a> = /dev/stdout". </p> + +<li> <p> Start Postfix with "<b>postfix start-fg</b>". </p> + +</ol> + +<h2> <a name="logrotate"> Rotating logs </a> </h2> + +<p> The command "<b>postfix logrotate</b>" may be run by hand or +by a cronjob. It logs all errors, and reports errors to stderr if +run from a terminal. This command implements the following steps: +</p> + +<ul> + +<li> <p> Rename the current logfile by appending a suffix that +contains the date and time. This suffix is configured with the +<a href="postconf.5.html#maillog_file_rotate_suffix">maillog_file_rotate_suffix</a> parameter (default: %Y%m%d-%H%M%S). </p> + +<li> <p> Reload Postfix so that <a href="postlogd.8.html">postlogd(8)</a> immediately closes the +old logfile. </p> + +<li> <p> After a brief pause, compress the old logfile. The compression +program is configured with the <a href="postconf.5.html#maillog_file_compressor">maillog_file_compressor</a> parameter +(default: gzip). </p> + +</ul> + +<p> Notes: </p> + +<ul> + +<li> <p> This command will not rotate a logfile with pathname under +the /dev directory, such as /dev/stdout. </p> + +<li> <p> This command does not (yet) remove old logfiles. </p> + +</ul> + +<h2> <a name="limitations">Limitations</a> </h2> + +<p> Background: </p> + +<ul> + +<li> <p> Postfix consists of a number of daemon programs that run +in the background, as well as non-daemon programs for local mail +submission or Postfix management. + +<li> <p> Logging to Postfix logfile or stdout requires the Postfix +<a href="postlogd.8.html">postlogd(8)</a> service. This ensures that simultaneous logging from +different programs will not get mixed up. </p> + +<li> <p> All Postfix programs can log to syslog, but not all programs +have sufficient privileges to use the Postfix logging service, and +many non-daemon programs must not log to stdout as that would corrupt +their output. </p> + +</ul> + +<p> Limitations: </p> + +<ul> + +<li> <p> Non-daemon Postfix programs will log errors to syslogd(8) +before they have processed command-line options and <a href="postconf.5.html">main.cf</a> parameters. + +<li> <p> If Postfix is down, the non-daemon programs <a href="postfix.1.html">postfix(1)</a>, +<a href="postsuper.1.html">postsuper(1)</a>, <a href="postmulti.1.html">postmulti(1)</a>, and <a href="postlog.1.html">postlog(1)</a>, will log directly to +$<a href="postconf.5.html#maillog_file">maillog_file</a>. These programs expect to run with root privileges, +for example during Postfix start-up, reload, or shutdown. + +<li> <p> Other non-daemon Postfix programs will never write directly +to $<a href="postconf.5.html#maillog_file">maillog_file</a> (also, logging to stdout would interfere with the +operation of some of these programs). These programs can log to +<a href="postlogd.8.html">postlogd(8)</a> if they are run by the super-user, or if their executable +file has set-gid permission. Do not set this permission on programs +other than <a href="postdrop.1.html">postdrop(1)</a> and <a href="postqueue.1.html">postqueue(1)</a>. + +</ul> + +</body> + +</html> |