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SYSLOG.CONF(5)              BSD File Formats Manual             SYSLOG.CONF(5)

NAME
     syslog.conf -- syslogd(8) configuration file

DESCRIPTION
     The syslog.conf file is the configuration file for the syslogd(8) pro-
     gram.  It consists of blocks of lines separated by program specifica-
     tions, with each line containing two fields: the selector field which
     specifies the types of messages and priorities to which the line applies,
     and an action field which specifies the action to be taken if a message
     syslogd(8) receives matches the selection criteria.  The selector field
     is separated from the action field by one or more tab characters.

     The selectors are encoded as a facility, a period ('.'), and a level,
     with no intervening whitespace.  Both the facility and the level are case
     insensitive.

     The facility describes the part of the system generating the message, and
     is one of the following keywords: auth, authpriv, cron, daemon, ftp,
     kern, lpr, mail, mark, news, syslog, user, uucp and local0 through
     local7.  These keywords (with the exception of mark) correspond to the
     similar ``LOG_'' values specified to the openlog(3) and syslog(3) library
     routines.

     The level describes the severity of the message, and is a keyword from
     the following ordered list (highest to lowest): emerg, alert, crit, err,
     warning, notice, info and debug.  These keywords correspond to the simi-
     lar (LOG_) values specified to the syslog(3) library routine.

     Each block of lines is separated from the previous block by a tag.  The
     tag is a line beginning with !prog and each block will be associated with
     calls to syslog from that specific program.  When a message matches mul-
     tiple blocks, the action of each matching block is taken.  If no tag is
     specified at the beginning of the file, every line is checked for a match
     and acted upon (at least until a tag is found).

     !!prog causes the subsequent block to abort evaluation when a message
     matches, ensuring that only a single set of actions is taken.  !* can be
     used to ensure that any ensuing blocks are further evaluated (i.e. can-
     celling the effect of a !prog or !!prog).

     See syslog(3) for further descriptions of both the facility and level
     keywords and their significance.  It's recommended that selections be
     made on facility rather than program, since the latter can easily vary in
     a networked environment.  In some cases, though, an appropriate facility
     simply doesn't exist.

     If a received message matches the specified facility and is of the speci-
     fied level (or a higher level), and the first word in the message after
     the date matches the program, the action specified in the action field
     will be taken.

     Multiple selectors may be specified for a single action by separating
     them with semicolon (';') characters.  It is important to note, however,
     that each selector can modify the ones preceding it.

     Multiple facilities may be specified for a single level by separating
     them with comma (',') characters.

     An asterisk ('*') can be used to specify all facilities, all levels or
     all programs.

     The special facility ``mark'' receives a message at priority ``info''
     every 20 minutes (see syslogd(8)).  This is not enabled by a facility
     field containing an asterisk.

     The special level ``none'' disables a particular facility.

     The action field of each line specifies the action to be taken when the
     selector field selects a message.  There are six forms:

     o   A pathname (beginning with a leading slash).  Selected messages are
         appended to the file.

     o   A pipe to another program (beginning with a leading pipe symbol).
         The given program is started and presented the selected messages on
         its standard input.  If the program exits, syslogd(8) tries to
         restart it.

     o   A hostname (preceded by an at ('@') sign).  Selected messages are
         forwarded to the syslogd(8) program on the named host.  A port number
         may be specified using the host:port syntax.  This is optional for
         UDP and TLS.  There is no well-known port for syslog over TCP, so in
         this case it is mandatory to specify the port.  IPv6 addresses can be
         used by surrounding the address portion with square brackets ('[' and
         ']').  A prefix udp4:// or udp6:// in front of the hostname and after
         the at sign will force IPv4 or IPv6 addresses for UDP transport.  The
         prefixes tcp[46]:// or tls[46]:// send messages over TCP or TLS,
         respectively, with an optional IP version 4 or 6.

     o   A comma separated list of users.  Selected messages are written to
         those users if they are logged in.

     o   An asterisk.  Selected messages are written to all logged-in users.

     o   A colon, followed by a memory buffer size (in kilobytes), followed by
         another colon, followed by a buffer name.  Selected messages are
         written to an in-memory buffer that may be read using syslogc(8).
         Memory buffered logging is useful to provide access to log data on
         devices that lack local storage (e.g. diskless workstations or
         routers).  The largest allowed buffer size is 256kb.

     Blank lines and lines whose first non-blank character is a hash ('#')
     character are ignored.

FILES
     /etc/syslog.conf  The syslogd(8) configuration file.

EXAMPLES
     A configuration file might appear as follows:

     # Log info (and higher) messages from spamd only to
     # a dedicated file, discarding debug messages.
     # Matching messages abort evaluation of further rules.
     !!spamd
     daemon.info                                             /var/log/spamd
     daemon.debug                                            /dev/null
     !*

     # Log all kernel messages, authentication messages of
     # level notice or higher and anything of level err or
     # higher to the console.
     # Don't log private authentication messages!
     *.err;kern.*;auth.notice;authpriv.none                  /dev/console

     # Log anything (except mail) of level info or higher.
     # Don't log private authentication messages!
     *.info;mail.none;authpriv.none                          /var/log/messages

     # The authpriv file has restricted access.
     authpriv.*                                              /var/log/secure

     # Log all the mail messages in one place.
     mail.*                                                  /var/log/maillog

     # Everybody gets emergency messages, plus log them on another
     # machine.
     *.emerg                                                 *
     *.emerg                                                 @arpa.berkeley.edu

     # Root and Eric get alert and higher messages.
     *.alert                                                 root,eric

     # Save mail and news errors of level err and higher in a
     # special file.
     mail,news.err                                           /var/log/spoolerr

     # Save ftpd transactions along with mail and news
     !ftpd
     *.*                                                     /var/log/spoolerr

     # Keep a copy of all logging in a 32k memory buffer named "debug"
     *.debug                                                 :32:debug

     # Store notices and authpriv messages in a 64k buffer named "important"
     *.notice,authpriv.*                                     :64:important

     # feed everything to logsurfer
     *.*                                             |/usr/local/sbin/logsurfer

SEE ALSO
     syslog(3), syslogc(8), syslogd(8)

HISTORY
     The syslog.conf file appeared in 4.3BSD, along with syslogd(8).

BUGS
     The effects of multiple selectors are sometimes not intuitive.  For exam-
     ple ``mail.crit;*.err'' will select ``mail'' facility messages at the
     level of ``err'' or higher, not at the level of ``crit'' or higher.

BSD                            February 10, 2015                           BSD