NAME

syslogd — log systems messages

SYNOPSIS

DESCRIPTION

syslogd reads and logs messages to the system console, log files, pipes to other programs, other machines and/or users as specified by its configuration file.

The options are as follows:

-a path

Specify a location where syslogd should place an additional log socket. Up to about 20 additional logging sockets can be specified. The primary use for this is to place additional log sockets in /dev/log of various chroot filespaces, though the need for these is less urgent after the introduction of sendsyslog(2).

-d

Enable debugging to the standard output, and do not disassociate from the controlling terminal.

-f config_file

Specify the pathname of an alternate configuration file; the default is /etc/syslog.conf.

-h

Include the hostname when forwarding messages to a remote host.

-m mark_interval

Select the number of minutes between “mark” messages; the default is 20 minutes.

-n

Print source addresses numerically rather than symbolically. This saves an address-to-name lookup for each incoming message, which can be useful when combined with the -u option on a loghost with no DNS cache. Messages from the local host will still be logged with the symbolic local host name.

-p log_socket

Specify the pathname of an alternate log socket to be used instead; the default is /dev/log.

-s reporting_socket

Specify path to an AF_LOCAL socket for use in reporting logs stored in memory buffers using syslogc(8).

-u

Select the historical “insecure” mode, in which syslogd will accept input from the UDP port. Some software wants this, but you can be subjected to a variety of attacks over the network, including attackers remotely filling logs.

syslogd reads its configuration file when it starts up and whenever it receives a hangup signal. For information on the format of the configuration file, see syslog.conf(5).

syslogd creates the file /var/run/syslog.pid, and stores its process ID there. This can be used to kill or reconfigure syslogd.

syslogd opens an Internet domain socket as specified in /etc/services. Normally syslogd will only use this socket to send messages outwards, but in “insecure” mode it will also read messages from this socket. syslogd also opens and reads messages from the UNIX-domain socket /dev/log, and from the special device /dev/klog (to read kernel messages).

syslogd opens the above described socket whether or not it is running in secure mode. If syslogd is running in secure mode, all incoming data on this socket is discarded. The socket is required for sending forwarded messages.

The message sent to syslogd should consist of a single line. The message can contain a priority code, which should be a preceding decimal number in angle braces, for example, “⟨5⟩”. This priority code should map into the priorities defined in the include file <sys/syslog.h>.

FILES

/etc/syslog.conf

configuration file

/var/run/syslog.pid

process ID of current syslogd

/dev/log

name of the UNIX-domain datagram log socket

/dev/klog

kernel log device

SEE ALSO

logger(1), syslog(3), services(5), syslog.conf(5), newsyslog(8), syslogc(8)

HISTORY

The syslogd command appeared in 4.3BSD.

CAVEATS

syslogd does not create files, it only logs to existing ones.