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28 .\" @(#)syslogd.8 8.1 (Berkeley) 6/6/93
36 .Nd log systems messages
39 .Op Fl 468ACcdFkNnosTuv
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/masklen[:service]XX"
113 Accept datagrams from
115 (in the usual dotted quad notation) with
117 bits being taken into account when doing the address comparison.
119 can be also IPv6 address by enclosing the address with
125 is the name or number of an UDP service (see
127 the source packet must belong to.
132 allows packets being sent from any UDP port.
139 is IPv4 address, a missing
141 will be substituted by the historic class A or class B netmasks if
143 belongs into the address range of class A or B,
151 will be substituted by 128.
154 .Ar domainname Op \&: Ar service
157 Accept datagrams where the reverse address lookup yields
159 for the sender address.
162 is as explained above.
164 can contain special characters of a shell-style pattern such as
170 options are ignored if the
172 option is also specified.
176 .Ar bind_address Op \&: Ar service
185 Bind to a specific address and/or port.
186 The address can be specified as a hostname,
187 and the port as a service name.
188 If an IPv6 address is specified, it should be enclosed with
196 This option can be specified multiple times to bind to
197 multiple addresses and/or ports.
199 Create log files that do not exist
200 .Pq permission is set to Ql Li 0600 .
202 Disable the compression of repeated instances of the same line
203 into a single line of the form
204 .Dq Li "last message repeated N times"
205 when the output is a pipe to another program.
207 disable this compression in all cases.
212 This is probably only of use to developers working on
214 .It Fl f Ar config_file
215 Specify the pathname of an alternate configuration file;
217 .Pa /etc/syslog.conf .
222 rather than going into daemon mode.
223 This is useful if some other process uses
229 and wants to monitor when and how it exits.
231 Disable the translation of
232 messages received with facility
238 facility is reserved for messages read directly from
240 .It Fl m Ar mark_interval
241 Select the number of minutes between
244 the default is 20 minutes.
246 Disable binding on UDP sockets.
247 RFC 3164 recommends that outgoing
249 messages should originate from the privileged port,
252 the recommended behavior.
256 Disable DNS query for every request.
258 Prefix kernel messages with the full kernel boot file as determined by
260 Without this, the kernel message prefix is always
262 .It Fl p Ar log_socket
263 Specify the pathname of an alternate log socket to be used instead;
268 options are specified,
269 the default pathname is replaced with the specified one.
272 options are specified,
273 the remaining pathnames are treated as additional log sockets.
275 Specify an alternative file in which to store the process ID.
277 .Pa /var/run/syslog.pid .
278 .It Fl S Ar logpriv_socket
279 Specify the pathname of an alternate log socket for privileged
280 applications to be used instead;
282 .Pa /var/run/logpriv .
285 options are specified,
286 the default pathname is replaced with the specified one.
289 options are specified,
290 the remaining pathnames are treated as additional log sockets.
291 .It Fl l Oo Ar mode Ns \&: Oc Ns Ar path
292 Specify a location where
294 should place an additional log socket.
295 The primary use for this is to place additional log sockets in
297 of various chroot filespaces.
298 File permissions for socket can be specified in octal representation in
300 delimited with a colon.
301 The socket location must be specified as an absolute pathname in
304 Operate in secure mode.
305 Do not log messages from remote machines.
307 no network socket will be opened at all,
308 which also disables logging to remote machines.
310 Always use the local time and date for messages received from the network,
311 instead of the timestamp field supplied in the message by the remote host.
312 This is useful if some of the originating hosts can't keep time properly
313 or are unable to generate a correct timestamp.
315 Unique priority logging.
316 Only log messages at the specified priority.
318 messages at the stated priority or higher are logged.
319 This option changes the default comparison from
326 the numeric facility and priority are
327 logged with each locally-written message.
328 If specified more than once,
329 the names of the facility and priority are logged with each locally-written
335 utility reads its configuration file when it starts up and whenever it
336 receives a hangup signal.
337 For information on the format of the configuration file,
343 utility reads messages from the
348 .Pa /var/run/logpriv ,
349 from an Internet domain socket specified in
351 and from the special device
353 .Pq to read kernel messages .
357 utility creates its process ID file,
359 .Pa /var/run/syslog.pid ,
360 and stores its process
362 This can be used to kill or reconfigure
367 should consist of a single line.
368 The message can contain a priority code,
369 which should be a preceding
370 decimal number in angle braces,
373 This priority code should map into the priorities defined in the
377 For security reasons,
379 will not append to log files that do not exist
383 therefore, they must be created manually before running
386 The date and time are taken from the received message.
387 If the format of the timestamp field is incorrect,
388 time obtained from the local host is used instead.
389 This can be overridden by the
393 .Bl -tag -width /var/run/syslog.pid -compact
394 .It Pa /etc/syslog.conf
396 .It Pa /var/run/syslog.pid
397 default process ID file
401 domain datagram log socket
402 .It Pa /var/run/logpriv
404 socket for privileged applications
430 The ability to log messages received in UDP packets is equivalent to
431 an unauthenticated remote disk-filling service,
432 and should probably be disabled by default.
434 .No inter- Ns Nm syslogd
435 authentication mechanism ought to be worked out.
436 To prevent the worst abuse,
439 option is therefore highly recommended.
443 matching algorithm does not pretend to be very efficient;
444 use of numeric IP addresses is faster than domain name comparison.
445 Since the allowed peer list is being walked linearly,
446 peer groups where frequent messages are being anticipated
447 from should be put early into the
451 The log socket was moved from
453 to ease the use of a read-only root file system.
455 some old binaries so that a symbolic link might be used for a