SYSLOG.CONF(5)SYSLOG.CONF(5)NAMEsyslog.conf - syslogd(8) configuration file
DESCRIPTION
The syslog.conf file is the main configuration file for the syslogd(8)
which logs system messages on *nix systems. This file specifies rules
for logging. For special features see the syslogd(8) manpage. Every
rule consists of two fields, a selector field and an action field.
These two fields are separated by one or more tabs. The selector field
specifies a pattern of facilities and priorities belonging to the spec‐
ified action. Lines starting with a hash mark (``#'') and empty lines
are ignored.
SELECTORS
The selector field itself again consists of two parts, a facility and a
priority, separated by a period (``.''). Both parts are case insensi‐
tive and can also be specified as decimal numbers, but don't do that,
you have been warned. Both facilities and priorities are described in
syslog(3). The names mentioned below correspond to the similar
LOG_-values in /usr/include/syslog.h. The facility is one of the fol‐
lowing keywords: auth, authpriv, cron, daemon, kern, lpr, mail, mark,
news, security (same as auth), syslog, user, uucp and local0 through
local7. The keyword security should not be used anymore and mark is
only for internal use and therefore should not be used in applications.
Anyway, you may want to specify and redirect these messages here. The
facility specifies the subsystem that produced the message, i.e. all
mail programs log with the mail facility (LOG_MAIL) if they log using
syslog.
The priority is one of the following keywords, in ascending order:
debug, info, notice, warning, warn (same as warning), err, error (same
as err), crit, alert, emerg, panic (same as emerg). The keywords
error, warn and panic are deprecated and should not be used anymore.
The priority defines the severity of the message
The behavior of the original BSD syslogd is that all messages of the
specified priority and higher are logged according to the given action.
This syslogd(8) behaves the same, but has some extensions.
In addition to the above mentioned names the syslogd(8) understands the
following extensions:
* An asterisk (``*'') before the period stands for all facilities.
none The keyword none stands for no priority of the given facility.
Multiple selectors may be specified for a single action using the semi‐
colon (``;'') separator. Remember that each selector in the selector
field is capable to overwrite the preceding ones. Using this behavior
you can exclude some priorities from the pattern.
ACTIONS
The action field of a rule describes the abstract term ``logfile''. A
``logfile'' need not to be a real file, btw. The syslogd(8) provides
the following actions.
Regular File
Typically messages are logged to real files. The file has to be speci‐
fied with full pathname, beginning with a slash ``/''.
Terminal and Console
If the file you specified is a tty, special tty-handling is done, same
with /dev/console.
Remote Machine
This release does not implement remote logging, i.e. the ability to
send messages to a remote host running syslogd(8). To forward messages
to another host, prepend the hostname with the at sign (``@'').
List of Users
Usually critical messages are also directed to ``root'' on that
machine. You can specify a list of users that shall get the message by
simply writing the login. You may specify more than one user by sepa‐
rating them with commas (``,''). If they're logged in they get the mes‐
sage. Don't think a mail would be sent, that might be too late.
Everyone logged on
Emergency messages often go to all users currently online to notify
them that something strange is happening with the system. To specify
this wall(1)-feature use an asterisk (``*'').
EXAMPLES
Here are some example, partially taken from a real existing site and
configuration. Hopefully they rub out all questions to the configura‐
tion, if not, drop me (Joey) a line.
# Store critical stuff in critical
#
*.crit /var/adm/critical
This will store all messages with the priority crit in the file
/var/adm/critical.
# The tcp wrapper loggs with mail.info, we display
# all the connections on tty12
#
mail.info /dev/tty12
This directs all messages that uses mail.info (in source LOG_MAIL |
LOG_INFO) to /dev/tty12, the 12th console.
# Log all mail.info and news.info messages to info
#
mail,news.info /var/adm/info
This will extract all messages that come either with mail.info or with
news.info and store them in the file /var/adm/info.
# Emergency messages will be displayed using wall
#
*.emerg *
This rule tells the syslogd to write all emergency messages to all cur‐
rently logged in users. This is the wall action.
# Messages of the priority alert will be directed
# to the operator
#
*.alert root,joey
This rule directs all messages with a priority of alert or higher to
the terminals of the operator, i.e. of the users ``root'' and ``joey''
if they're logged in.
*.* @finlandia
This rule would redirect all messages to a remote host called finlan‐
dia. This is useful especially in a cluster of machines where all sys‐
log messages will be stored on only one machine.
FILES
/etc/syslog.conf Configuration file for syslogd
BUGS
The effects of multiple selectors are sometimes not intuitive. For
example ``mail.crit,*.err'' will select ``mail'' facility messages at
the level of ``err'' or higher, not at the level of ``crit'' or higher.
SEE ALSOsyslogd(8), logger(1), syslog(3)AUTHORS
The syslogd is taken from BSD sources, Greg Wettstein
(greg@wind.rmcc.com) performed the port to Linux, Martin Schulze
(joey@linux.de) made some bugfixes and added some new features.
1 January 1998 SYSLOG.CONF(5)
