NAME
syslogd
- log systems messages
SYNOPSIS
syslogd
[-dnrSsTUv]
[-b bind_address]
[-f config_file]
[-g group]
[-m mark_interval]
[-P file_list]
[-p log_socket2 ...]
[-p log_socket]
[-t chroot_dir]
[-u user]
DESCRIPTION
syslogd
reads and logs messages to the system console, log files, other
machines and/or users as specified by its configuration file.
The options are as follows:
- -b bind_address
-
Specify one specific IP address or hostname to bind to.
If a hostname is specified, the IPv4 or IPv6 address
which corresponds to it is used.
- -d
-
Enable debugging to the standard output,
and do not disassociate from the controlling terminal.
- -f
-
Specify the pathname of an alternative configuration file;
the default is
/etc/syslog.conf
.
- -g group
-
Set GID to
group
after the sockets and log files have been opened.
- -m
-
Select the number of minutes between ``mark'' messages;
the default is 20 minutes.
- -n
-
Do not perform hostname lookups; report only numeric addresses.
- -P
-
Specify the pathname of a file containing a list of sockets to be
created.
The format of the file is simply one socket per line.
- -p
-
Specify the pathname of a log socket.
Multiple
-p
options create multiple log sockets.
If no
-p
arguments are created, the default socket of
/var/run/log
is used.
- -r
-
Disable the compression of repeated instances of the same line
into a single line of the form
``last message repeated N times''.
- -S
-
Sync kernel messages to disk immediately.
- -s
-
Select
``secure''
mode, in which
syslogd
does not listen on a UDP socket but only communicates over a
UNIX
domain socket.
This is valuable when the machine on
which
syslogd
runs is subject to attack over the network and it is desired
that the machine be protected from attempts to remotely fill logs
and similar attacks.
- -t chroot_dir
-
chroot(2)
to
chroot_dir
after the sockets and log files have been opened.
- -T
-
Always use the local time and date for messages received from the
network, instead of the timestamp field supplied in the message
by the remote host.
This is useful if some of the originating hosts can't keep time
properly or are unable to generate a correct timestamp.
- -u user
-
Set UID to
user
after the sockets and log files have been opened.
- -U
-
Unique priority logging.
Only log messages at the priority specified by the selector in the
configuration file.
Without this option, messages at the specified priority or higher are
logged.
This option changes the default priority comparison from
`>='
to
`='.
- -v
-
Verbose logging.
If specified once, the numeric facility and priority are logged with
each locally-written message.
If specified more than once, the names of the facility and priority are
logged with each locally-written message.
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
reads messages from the
UNIX
domain socket
/var/run/log
,
from an Internet domain socket specified in
/etc/services
,
and from the special device
/dev/klog
(to read kernel messages).
syslogd
creates the file
/var/run/syslogd.pid
,
and stores its process
id there.
This can be used to kill or reconfigure
.
By using multiple
-p
options, one can set up many chroot environments by passing the pathname
to the log socket
(/var/run/log
)
in each chroot area to
.
For example:
syslogd
-p
/var/run/log
-p
/web/var/run/log
-p
/ftp/var/run/log
Note: the normal log socket must now also be passed to
.
The logged message includes the date, time, and hostname (or pathname of
the log socket).
Commonly, the program name and the process id is included.
The date and time are taken from the received message.
If the format of the timestamp field is incorrect, time obtained from
the local host is used instead.
This can be overridden by the
-T
flag.
Accesses from UDP socket can be filtered by libwrap configuration files, like
/etc/hosts.deny
.
Specify
``
syslogd
''
in
daemon_list
portion of the configuration files.
Refer to
hosts_access(5)
for details.
SYSLOG PROTOCOL NOTES
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
>.
See RFC 3164 for detailed description of the message format.
Messages from the local kernel that are not tagged with a priority code
receive the default facility
LOG_KERN
and priority
LOG_NOTICE
.
All other untagged messages receive the default facility
LOG_USER
and priority
LOG_NOTICE
.
FILES
/etc/syslog.conf
-
The configuration file.
/var/run/syslogd.pid
-
The process id of current
.
/var/run/log
-
Name of the
UNIX
domain datagram log socket.
/dev/klog
-
The kernel log device.
SEE ALSO
logger(1),
syslog(3),
services(5),
syslog.conf(5),
newsyslog(8)
HISTORY
The
syslogd
command appeared in
4.3BSD.
Support for multiple log sockets appeared in
NetBSD1.4.
libwrap support appeared in
NetBSD1.6.