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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
46 .Op Fl p Ar log_socket
47 .Op Fl S Ar logpriv_socket
51 utility reads and logs messages to the system console,
54 machines and/or users as specified by its configuration file.
56 The options are as follows:
57 .Bl -tag -width indent
61 to use IPv4 addresses only.
65 to use IPv6 addresses only.
69 not to interfere with 8-bit data.
72 will replace C1 control characters
73 .Pq ISO 8859 and Unicode characters
77 Note, this option does not change the way
79 alters control characters
80 .Pq see Xr iscntrl 3 .
81 They will always be replaced with their
87 tries to send the message to only one address
88 even if the host has more than one A or AAAA record.
89 If this option is specified,
91 tries to send the message to all addresses.
92 .It Fl a Ar allowed_peer
100 options may be specified.
104 option may be any of the following:
105 .Bl -tag -width "ipaddr[/prefixlen][:service]XX"
117 Accept datagrams from
120 can be specified as an IPv4 address or as an IPv6
121 address enclosed with
127 is the name or number of an UDP service (see
129 the source packet must belong to.
134 accepts UDP packets from any source port.
141 is IPv4 address, a missing
143 will be substituted by the historic class A or class B netmasks if
145 belongs into the address range of class A or B,
153 will be substituted by 128.
156 .Ar domainname Op \&: Ar service
159 Accept datagrams where the reverse address lookup yields
161 for the sender address.
164 is as explained above.
166 can contain special characters of a shell-style pattern such as
172 options are ignored if the
174 option is also specified.
178 .Ar bind_address Op \&: Ar service
187 Bind to a specific address and/or port.
188 The address can be specified as a hostname,
189 and the port as a service name.
190 If an IPv6 address is specified, it should be enclosed with
198 This option can be specified multiple times to bind to
199 multiple addresses and/or ports.
201 Create log files that do not exist
202 .Pq permission is set to Ql Li 0600 .
204 Disable the compression of repeated instances of the same line
205 into a single line of the form
206 .Dq Li "last message repeated N times"
207 when the output is a pipe to another program.
209 disable this compression in all cases.
214 This is probably only of use to developers working on
216 .It Fl f Ar config_file
217 Specify the pathname of an alternate configuration file;
219 .Pa /etc/syslog.conf .
224 rather than going into daemon mode.
225 This is useful if some other process uses
231 and wants to monitor when and how it exits.
233 When logging remote messages use hostname from the message (if supplied)
234 instead of using address from which the message was received.
236 Disable the translation of
237 messages received with facility
243 facility is reserved for messages read directly from
245 .It Fl m Ar mark_interval
246 Select the number of minutes between
249 the default is 20 minutes.
251 Disable binding on UDP sockets.
252 RFC 3164 recommends that outgoing
254 messages should originate from the privileged port,
257 the recommended behavior.
261 Disable DNS query for every request.
263 Prefix kernel messages with the full kernel boot file as determined by
265 Without this, the kernel message prefix is always
267 .It Fl p Ar log_socket
268 Specify the pathname of an alternate log socket to be used instead;
274 the default pathname is replaced with the specified one.
277 options are specified,
278 the remaining pathnames are treated as additional log sockets.
280 Specify an alternative file in which to store the process ID.
282 .Pa /var/run/syslog.pid .
283 .It Fl S Ar logpriv_socket
284 Specify the pathname of an alternate log socket for privileged
285 applications to be used instead;
287 .Pa /var/run/logpriv .
291 the default pathname is replaced with the specified one.
294 options are specified,
295 the remaining pathnames are treated as additional log sockets.
296 .It Fl l Oo Ar mode Ns \&: Oc Ns Ar path
297 Specify a location where
299 should place an additional log socket.
300 The primary use for this is to place additional log sockets in
302 of various chroot filespaces.
303 File permissions for socket can be specified in octal representation in
305 delimited with a colon.
306 The socket location must be specified as an absolute pathname in
309 Operate in secure mode.
310 Do not log messages from remote machines.
312 no network socket will be opened at all,
313 which also disables logging to remote machines.
315 Always use the local time and date for messages received from the network,
316 instead of the timestamp field supplied in the message by the remote host.
317 This is useful if some of the originating hosts cannot keep time properly
318 or are unable to generate a correct timestamp.
320 Unique priority logging.
321 Only log messages at the specified priority.
323 messages at the stated priority or higher are logged.
324 This option changes the default comparison from
331 the numeric facility and priority are
332 logged with each locally-written message.
333 If specified more than once,
334 the names of the facility and priority are logged with each locally-written
340 utility reads its configuration file when it starts up and whenever it
341 receives a hangup signal.
342 For information on the format of the configuration file,
348 utility reads messages from the
353 .Pa /var/run/logpriv ,
354 from an Internet domain socket specified in
356 and from the special device
358 .Pq to read kernel messages .
362 utility creates its process ID file,
364 .Pa /var/run/syslog.pid ,
365 and stores its process
367 This can be used to kill or reconfigure
372 should consist of a single line.
373 The message can contain a priority code,
374 which should be a preceding
375 decimal number in angle braces,
378 This priority code should map into the priorities defined in the
382 For security reasons,
384 will not append to log files that do not exist
388 therefore, they must be created manually before running
391 The date and time are taken from the received message.
392 If the format of the timestamp field is incorrect,
393 time obtained from the local host is used instead.
394 This can be overridden by the
398 .Bl -tag -width /var/run/syslog.pid -compact
399 .It Pa /etc/syslog.conf
401 .It Pa /var/run/syslog.pid
402 default process ID file
406 domain datagram log socket
407 .It Pa /var/run/logpriv
409 socket for privileged applications
435 The ability to log messages received in UDP packets is equivalent to
436 an unauthenticated remote disk-filling service,
437 and should probably be disabled by default.
439 .No inter- Ns Nm syslogd
440 authentication mechanism ought to be worked out.
441 To prevent the worst abuse,
444 option is therefore highly recommended.
448 matching algorithm does not pretend to be very efficient;
449 use of numeric IP addresses is faster than domain name comparison.
450 Since the allowed peer list is being walked linearly,
451 peer groups where frequent messages are being anticipated
452 from should be put early into the
456 The log socket was moved from
458 to ease the use of a read-only root file system.
460 some old binaries so that a symbolic link might be used for a