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28 .\" @(#)syslogd.8 8.1 (Berkeley) 6/6/93
36 .Nd log systems messages
39 .Op Fl 468ACcdFHkNnosTuv
40 .Op Fl a Ar allowed_peer
41 .Op Fl b Ar bind_address
42 .Op Fl f Ar config_file
43 .Op Fl l Oo Ar mode Ns \&: Oc Ns Ar path
44 .Op Fl m Ar mark_interval
47 .Op Fl p Ar log_socket
48 .Op Fl S Ar logpriv_socket
52 utility reads and logs messages to the system console,
55 machines and/or users as specified by its configuration file.
57 The options are as follows:
58 .Bl -tag -width indent
62 to use IPv4 addresses only.
66 to use IPv6 addresses only.
70 not to interfere with 8-bit data.
73 will replace C1 control characters
74 .Pq ISO 8859 and Unicode characters
78 Note, this option does not change the way
80 alters control characters
81 .Pq see Xr iscntrl 3 .
82 They will always be replaced with their
88 tries to send the message to only one address
89 even if the host has more than one A or AAAA record.
90 If this option is specified,
92 tries to send the message to all addresses.
93 .It Fl a Ar allowed_peer
101 options may be specified.
105 option may be any of the following:
106 .Bl -tag -width "ipaddr[/prefixlen][:service]XX"
118 Accept datagrams from
121 can be specified as an IPv4 address or as an IPv6
122 address enclosed with
128 is the name or number of an UDP service (see
130 the source packet must belong to.
135 accepts UDP packets from any source port.
142 is IPv4 address, a missing
144 will be substituted by the historic class A or class B netmasks if
146 belongs into the address range of class A or B,
154 will be substituted by 128.
157 .Ar domainname Op \&: Ar service
160 Accept datagrams where the reverse address lookup yields
162 for the sender address.
165 is as explained above.
167 can contain special characters of a shell-style pattern such as
173 options are ignored if the
175 option is also specified.
179 .Ar bind_address Op \&: Ar service
188 Bind to a specific address and/or port.
189 The address can be specified as a hostname,
190 and the port as a service name.
191 If an IPv6 address is specified, it should be enclosed with
199 This option can be specified multiple times to bind to
200 multiple addresses and/or ports.
202 Create log files that do not exist
203 .Pq permission is set to Ql Li 0600 .
205 Disable the compression of repeated instances of the same line
206 into a single line of the form
207 .Dq Li "last message repeated N times"
208 when the output is a pipe to another program.
210 disable this compression in all cases.
215 This is probably only of use to developers working on
217 .It Fl f Ar config_file
218 Specify the pathname of an alternate configuration file;
220 .Pa /etc/syslog.conf .
225 rather than going into daemon mode.
226 This is useful if some other process uses
232 and wants to monitor when and how it exits.
234 When logging remote messages use hostname from the message (if supplied)
235 instead of using address from which the message was received.
237 Disable the translation of
238 messages received with facility
244 facility is reserved for messages read directly from
246 .It Fl m Ar mark_interval
247 Select the number of minutes between
250 the default is 20 minutes.
252 Disable binding on UDP sockets.
253 RFC 3164 recommends that outgoing
255 messages should originate from the privileged port,
258 the recommended behavior.
262 Disable DNS query for every request.
264 Select the output format of generated log messages.
269 are used to generate RFC 3164 log messages.
274 are used to generate RFC 5424 log messages,
275 having RFC 3339 timestamps with microsecond precision.
276 The default is to generate RFC 3164 log messages.
278 Prefix kernel messages with the full kernel boot file as determined by
280 Without this, the kernel message prefix is always
282 .It Fl p Ar log_socket
283 Specify the pathname of an alternate log socket to be used instead;
289 the default pathname is replaced with the specified one.
292 options are specified,
293 the remaining pathnames are treated as additional log sockets.
295 Specify an alternative file in which to store the process ID.
297 .Pa /var/run/syslog.pid .
298 .It Fl S Ar logpriv_socket
299 Specify the pathname of an alternate log socket for privileged
300 applications to be used instead;
302 .Pa /var/run/logpriv .
306 the default pathname is replaced with the specified one.
309 options are specified,
310 the remaining pathnames are treated as additional log sockets.
311 .It Fl l Oo Ar mode Ns \&: Oc Ns Ar path
312 Specify a location where
314 should place an additional log socket.
315 The primary use for this is to place additional log sockets in
317 of various chroot filespaces.
318 File permissions for socket can be specified in octal representation in
320 delimited with a colon.
321 The socket location must be specified as an absolute pathname in
324 Operate in secure mode.
325 Do not log messages from remote machines.
327 no network socket will be opened at all,
328 which also disables logging to remote machines.
330 Always use the local time and date for messages received from the network,
331 instead of the timestamp field supplied in the message by the remote host.
332 This is useful if some of the originating hosts cannot keep time properly
333 or are unable to generate a correct timestamp.
335 Unique priority logging.
336 Only log messages at the specified priority.
338 messages at the stated priority or higher are logged.
339 This option changes the default comparison from
346 the numeric facility and priority are
347 logged with each locally-written message.
348 If specified more than once,
349 the names of the facility and priority are logged with each locally-written
352 This option only affects the formatting of RFC 3164 messages.
353 Messages formatted according to RFC 5424 always include a
354 facility/priority number.
359 utility reads its configuration file when it starts up and whenever it
360 receives a hangup signal.
361 For information on the format of the configuration file,
367 utility reads messages from the
372 .Pa /var/run/logpriv ,
373 from an Internet domain socket specified in
375 and from the special device
377 .Pq to read kernel messages .
381 utility creates its process ID file,
383 .Pa /var/run/syslog.pid ,
384 and stores its process
386 This can be used to kill or reconfigure
391 should consist of a single line.
392 The message can contain a priority code,
393 which should be a preceding
394 decimal number in angle braces,
397 This priority code should map into the priorities defined in the
401 For security reasons,
403 will not append to log files that do not exist
407 therefore, they must be created manually before running
410 The date and time are taken from the received message.
411 If the format of the timestamp field is incorrect,
412 time obtained from the local host is used instead.
413 This can be overridden by the
417 .Bl -tag -width /var/run/syslog.pid -compact
418 .It Pa /etc/syslog.conf
420 .It Pa /var/run/syslog.pid
421 default process ID file
425 domain datagram log socket
426 .It Pa /var/run/logpriv
428 socket for privileged applications
454 The ability to log messages received in UDP packets is equivalent to
455 an unauthenticated remote disk-filling service,
456 and should probably be disabled by default.
458 .No inter- Ns Nm syslogd
459 authentication mechanism ought to be worked out.
460 To prevent the worst abuse,
463 option is therefore highly recommended.
467 matching algorithm does not pretend to be very efficient;
468 use of numeric IP addresses is faster than domain name comparison.
469 Since the allowed peer list is being walked linearly,
470 peer groups where frequent messages are being anticipated
471 from should be put early into the
475 The log socket was moved from
477 to ease the use of a read-only root file system.
479 some old binaries so that a symbolic link might be used for a