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33 .Nd log systems messages
36 .Op Fl 468ACcdFHkNnosTuv
37 .Op Fl a Ar allowed_peer
38 .Op Fl b Ar bind_address
39 .Op Fl f Ar config_file
40 .Op Fl l Oo Ar mode Ns \&: Oc Ns Ar path
41 .Op Fl M Ar fwd_length
42 .Op Fl m Ar mark_interval
45 .Op Fl p Ar log_socket
46 .Op Fl S Ar logpriv_socket
50 utility reads and logs messages to the system console,
53 machines and/or users as specified by its configuration file.
55 The options are as follows:
56 .Bl -tag -width indent
60 to use IPv4 addresses only.
64 to use IPv6 addresses only.
68 not to interfere with 8-bit data.
71 will replace C1 control characters
72 .Pq ISO 8859 and Unicode characters
76 Note, this option does not change the way
78 alters control characters
79 .Pq see Xr iscntrl 3 .
80 They will always be replaced with their
86 tries to send the message to only one address
87 even if the host has more than one A or AAAA record.
88 If this option is specified,
90 tries to send the message to all addresses.
91 .It Fl a Ar allowed_peer
99 options may be specified.
103 option may be any of the following:
104 .Bl -tag -width "ipaddr[/prefixlen][:service]XX"
116 Accept datagrams from
119 can be specified as an IPv4 address or as an IPv6
120 address enclosed with
126 is the name or number of an UDP service (see
128 the source packet must belong to.
133 accepts UDP packets from any source port.
140 is IPv4 address, a missing
142 will be substituted by the historic class A or class B netmasks if
144 belongs into the address range of class A or B,
152 will be substituted by 128.
155 .Ar domainname Op \&: Ar service
158 Accept datagrams where the reverse address lookup yields
160 for the sender address.
163 is as explained above.
165 can contain special characters of a shell-style pattern such as
171 options are ignored if the
173 option is also specified.
177 .Ar bind_address Op \&: Ar service
186 Bind to a specific address and/or port.
187 The address can be specified as a hostname,
188 and the port as a service name.
189 If an IPv6 address is specified, it should be enclosed with
197 This option can be specified multiple times to bind to
198 multiple addresses and/or ports.
200 Create log files that do not exist
201 .Pq permission is set to Ql Li 0600 .
203 Disable the compression of repeated instances of the same line
204 into a single line of the form
205 .Dq Li "last message repeated N times"
206 when the output is a pipe to another program.
208 disable this compression in all cases.
213 This is probably only of use to developers working on
215 .It Fl f Ar config_file
216 Specify the pathname of an alternate configuration file;
218 .Pa /etc/syslog.conf .
223 rather than going into daemon mode.
224 This is useful if some other process uses
230 and wants to monitor when and how it exits.
232 When logging remote messages use hostname from the message (if supplied)
233 instead of using address from which the message was received.
235 Disable the translation of
236 messages received with facility
242 facility is reserved for messages read directly from
244 .It Fl M Ar fwd_length
245 Set the limit on the length of forwarded messages.
246 The minimum is 480 octets.
247 The maximum for RFC 3164 output format is 1024 octets.
248 The default is 1024 octets.
249 .It Fl m Ar mark_interval
250 Select the number of minutes between
253 the default is 20 minutes.
255 Disable binding on UDP sockets.
256 RFC 3164 recommends that outgoing
258 messages should originate from the privileged port,
261 the recommended behavior.
265 Disable DNS query for every request.
267 Select the output format of generated log messages.
272 are used to generate RFC 3164 log messages.
277 are used to generate RFC 5424 log messages,
278 having RFC 3339 timestamps with microsecond precision.
279 The default is to generate RFC 3164 log messages.
281 Prefix kernel messages with the full kernel boot file as determined by
283 Without this, the kernel message prefix is always
285 .It Fl p Ar log_socket
286 Specify the pathname of an alternate log socket to be used instead;
292 the default pathname is replaced with the specified one.
295 options are specified,
296 the remaining pathnames are treated as additional log sockets.
298 Specify an alternative file in which to store the process ID.
300 .Pa /var/run/syslog.pid .
301 .It Fl S Ar logpriv_socket
302 Specify the pathname of an alternate log socket for privileged
303 applications to be used instead;
305 .Pa /var/run/logpriv .
309 the default pathname is replaced with the specified one.
312 options are specified,
313 the remaining pathnames are treated as additional log sockets.
314 .It Fl l Oo Ar mode Ns \&: Oc Ns Ar path
315 Specify a location where
317 should place an additional log socket.
318 The primary use for this is to place additional log sockets in
320 of various chroot filespaces.
321 File permissions for socket can be specified in octal representation in
323 delimited with a colon.
324 The socket location must be specified as an absolute pathname in
327 Operate in secure mode.
328 Do not log messages from remote machines.
330 no network socket will be opened at all,
331 which also disables logging to remote machines.
333 Always use the local time and date for messages received from the network,
334 instead of the timestamp field supplied in the message by the remote host.
335 This is useful if some of the originating hosts cannot keep time properly
336 or are unable to generate a correct timestamp.
338 Unique priority logging.
339 Only log messages at the specified priority.
341 messages at the stated priority or higher are logged.
342 This option changes the default comparison from
349 the numeric facility and priority are
350 logged with each locally-written message.
351 If specified more than once,
352 the names of the facility and priority are logged with each locally-written
355 This option only affects the formatting of RFC 3164 messages.
356 Messages formatted according to RFC 5424 always include a
357 facility/priority number.
362 utility reads its configuration file when it starts up and whenever it
363 receives a hangup signal.
364 For information on the format of the configuration file,
370 utility reads messages from the
375 .Pa /var/run/logpriv ,
376 from an Internet domain socket specified in
378 and from the special device
380 .Pq to read kernel messages .
384 utility creates its process ID file,
386 .Pa /var/run/syslog.pid ,
387 and stores its process
389 This can be used to kill or reconfigure
394 should consist of a single line.
395 The message can contain a priority code,
396 which should be a preceding
397 decimal number in angle braces,
400 This priority code should map into the priorities defined in the
404 For security reasons,
406 will not append to log files that do not exist
410 therefore, they must be created manually before running
413 The date and time are taken from the received message.
414 If the format of the timestamp field is incorrect,
415 time obtained from the local host is used instead.
416 This can be overridden by the
420 .Bl -tag -width /var/run/syslog.pid -compact
421 .It Pa /etc/syslog.conf
423 .It Pa /var/run/syslog.pid
424 default process ID file
428 domain datagram log socket
429 .It Pa /var/run/logpriv
431 socket for privileged applications
457 The ability to log messages received in UDP packets is equivalent to
458 an unauthenticated remote disk-filling service,
459 and should probably be disabled by default.
461 .No inter- Ns Nm syslogd
462 authentication mechanism ought to be worked out.
463 To prevent the worst abuse,
466 option is therefore highly recommended.
470 matching algorithm does not pretend to be very efficient;
471 use of numeric IP addresses is faster than domain name comparison.
472 Since the allowed peer list is being walked linearly,
473 peer groups where frequent messages are being anticipated
474 from should be put early into the
478 The log socket was moved from
480 to ease the use of a read-only root file system.
482 some old binaries so that a symbolic link might be used for a