From 5e61585d76ae77fd5e9e96ebabb57afa4d74880d Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sat, 27 Apr 2024 14:06:34 +0200 Subject: Adding upstream version 3.5.24. Signed-off-by: Daniel Baumann --- html/MAILLOG_README.html | 183 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 183 insertions(+) create mode 100644 html/MAILLOG_README.html (limited to 'html/MAILLOG_README.html') 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 @@ + + + + + + +Postfix logging to file or stdout + + + + + + + +

Postfix +logging to file or stdout

+ +

Overview

+ +

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.

+ +

Topics covered in this document:

+ +

Configuring logging to file + +
Configuring logging to stdout + +
Rotating logs + +
Limitations + +

+ +

Configuring logging to file

+ +

Logging to file solves a usability problem for MacOS, and +eliminates multiple problems for systemd-based systems.

+ +

Add the following line to master.cf if not already present +(note: there must be no whitespace at the start of the line):
+ +
+
```
+postlog   unix-dgram n  -       n       -       1       postlogd
+
```
+
+ +
Note: the service type "unix-dgram" was introduced with +Postfix 3.4. Remove the above line before backing out to an older +Postfix version.
+ +
Configure Postfix to write logging, to, for example, +/var/log/postfix.log. See also the "Logfile +rotation" section below for logfile management.
+ +
+
```
+# postfix stop
+# postconf maillog_file=/var/log/postfix.log
+# postfix start
+
```
+
+ +
By default, the logfile name must start with "/var" or "/dev/stdout" +(the list of allowed prefixes is configured with the maillog_file_prefixes +parameter). This safety mechanism limits the damage from a single +configuration mistake.
+ +

+ +

Configuring logging to stdout

+ +

Logging to stdout is useful when Postfix runs in a container, +as it eliminates a syslogd dependency.

+ +

Add the following line to master.cf if not already present (note: +there must be no whitespace at the start of the line):
+ +
+
```
+postlog   unix-dgram n  -       n       -       1       postlogd
+
```
+
+ +
Note: the service type "unix-dgram" was introduced with +Postfix 3.4. Remove the above line before backing out to an older +Postfix version.
+ +
Configure main.cf with "maillog_file = /dev/stdout".
+ +
Start Postfix with "postfix start-fg".
+ +

+ +

Rotating logs

+ +

The command "postfix logrotate" 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: +

+ +

Rename the current logfile by appending a suffix that +contains the date and time. This suffix is configured with the +maillog_file_rotate_suffix parameter (default: %Y%m%d-%H%M%S).
+ +
Reload Postfix so that postlogd(8) immediately closes the +old logfile.
+ +
After a brief pause, compress the old logfile. The compression +program is configured with the maillog_file_compressor parameter +(default: gzip).
+ +

+ +

Notes:

+ +

This command will not rotate a logfile with pathname under +the /dev directory, such as /dev/stdout.
+ +
This command does not (yet) remove old logfiles.
+ +

+ +

Limitations

+ +

Background:

+ +

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. + +
Logging to Postfix logfile or stdout requires the Postfix +postlogd(8) service. This ensures that simultaneous logging from +different programs will not get mixed up.
+ +
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.
+ +

+ +

Limitations:

+ +

Non-daemon Postfix programs will log errors to syslogd(8) +before they have processed command-line options and main.cf parameters. + +
If Postfix is down, the non-daemon programs postfix(1), +postsuper(1), postmulti(1), and postlog(1), will log directly to +$maillog_file. These programs expect to run with root privileges, +for example during Postfix start-up, reload, or shutdown. + +
Other non-daemon Postfix programs will never write directly +to $maillog_file (also, logging to stdout would interfere with the +operation of some of these programs). These programs can log to +postlogd(8) 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 postdrop(1) and postqueue(1). + +

+ + + + -- cgit v1.2.3