1.\" Copyright (c) 1983, 1986, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 4. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)syslogd.8 8.1 (Berkeley) 6/6/93 29.\" $FreeBSD$ 30.\" 31.Dd March 3, 2015 32.Dt SYSLOGD 8 33.Os 34.Sh NAME 35.Nm syslogd 36.Nd log systems messages 37.Sh SYNOPSIS 38.Nm 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 : Oc Ns Ar path 44.Op Fl m Ar mark_interval 45.Op Fl P Ar pid_file 46.Op Fl p Ar log_socket 47.Sh DESCRIPTION 48The 49.Nm 50utility reads and logs messages to the system console, log files, other 51machines and/or users as specified by its configuration file. 52.Pp 53The options are as follows: 54.Bl -tag -width indent 55.It Fl 4 56Force 57.Nm 58to use IPv4 addresses only. 59.It Fl 6 60Force 61.Nm 62to use IPv6 addresses only. 63.It Fl 8 64Tells 65.Nm 66not to interfere with 8-bit data. Normally 67.Nm 68will replace C1 control characters 69.Pq ISO 8859 and Unicode characters 70with their 71.Dq M- Ns Em x 72equivalent. 73Note, this option does not change the way 74.Nm 75alters control characters 76.Pq see Xr iscntrl 3 . 77They will always be replaced with their 78.Dq ^ Ns Em x 79equivalent. 80.It Fl A 81Ordinarily, 82.Nm 83tries to send the message to only one address 84even if the host has more than one A or AAAA record. 85If this option is specified, 86.Nm 87tries to send the message to all addresses. 88.It Fl a Ar allowed_peer 89Allow 90.Ar allowed_peer 91to log to this 92.Nm 93using UDP datagrams. 94Multiple 95.Fl a 96options may be specified. 97.Pp 98The 99.Ar allowed_peer 100option may be any of the following: 101.Bl -tag -width "ipaddr/masklen[:service]XX" 102.It Xo 103.Sm off 104.Ar ipaddr 105.No / Ar masklen 106.Op : Ar service 107.Sm on 108.Xc 109Accept datagrams from 110.Ar ipaddr 111(in the usual dotted quad notation) with 112.Ar masklen 113bits being taken into account when doing the address comparison. 114.Ar ipaddr 115can be also IPv6 address by enclosing the address with 116.Ql \&[ 117and 118.Ql \&] . 119If specified, 120.Ar service 121is the name or number of an UDP service (see 122.Xr services 5 ) 123the source packet must belong to. 124A 125.Ar service 126of 127.Ql \&* 128allows packets being sent from any UDP port. 129The default 130.Ar service 131is 132.Ql syslog . 133If 134.Ar ipaddr 135is IPv4 address, a missing 136.Ar masklen 137will be substituted by the historic class A or class B netmasks if 138.Ar ipaddr 139belongs into the address range of class A or B, respectively, or 140by 24 otherwise. 141If 142.Ar ipaddr 143is IPv6 address, a missing 144.Ar masklen 145will be substituted by 128. 146.It Xo 147.Sm off 148.Ar domainname Op : Ar service 149.Sm on 150.Xc 151Accept datagrams where the reverse address lookup yields 152.Ar domainname 153for the sender address. 154The meaning of 155.Ar service 156is as explained above. 157.It Xo 158.Sm off 159.No * Ar domainname Op : Ar service 160.Sm on 161.Xc 162Same as before, except that any source host whose name 163.Em ends 164in 165.Ar domainname 166will get permission. 167.El 168.Pp 169The 170.Fl a 171options are ignored if the 172.Fl s 173option is also specified. 174.It Xo 175.Fl b 176.Sm off 177.Ar bind_address Op : Ar service 178.Sm on 179.Xc 180.It Xo 181.Fl b 182.Sm off 183.Li : Ar service 184.Sm on 185.Xc 186Bind to a specific address and/or port. 187The address can be specified as a hostname, 188and the port as a service name. 189If an IPv6 address is specified, it should be enclosed with 190.Ql \&[ 191and 192.Ql \&] . 193The default 194.Ar service 195is 196.Ql syslog . 197.It Fl C 198Create log files that do not exist (permission is set to 199.Li 0600 ) . 200.It Fl c 201Disable the compression of repeated instances of the same line 202into a single line of the form 203.Dq Li "last message repeated N times" 204when the output is a pipe to another program. 205If specified twice, disable this compression in all cases. 206.It Fl d 207Put 208.Nm 209into debugging mode. 210This is probably only of use to developers working on 211.Nm . 212.It Fl f 213Specify the pathname of an alternate configuration file; 214the default is 215.Pa /etc/syslog.conf . 216.It Fl F 217Run 218.Nm 219in the foreground, rather than going into daemon mode. This is useful if 220some other process uses 221.Xr fork 2 222and 223.Xr exec 3 224to run 225.Nm , 226and wants to monitor when and how it exits. 227.It Fl k 228Disable the translation of 229messages received with facility 230.Dq kern 231to facility 232.Dq user . 233Usually the 234.Dq kern 235facility is reserved for messages read directly from 236.Pa /dev/klog . 237.It Fl m 238Select the number of minutes between 239.Dq mark 240messages; the default is 20 minutes. 241.It Fl N 242Disable binding on UDP sockets. RFC 3164 recommends that outgoing 243syslogd messages should originate from the privileged port, this 244option 245.Em disables 246the recommended behavior. This option inherits 247.Fl s . 248.It Fl n 249Disable dns query for every request. 250.It Fl o 251Prefix kernel messages with the full kernel boot file as determined by 252.Xr getbootfile 3 . 253Without this, the kernel message prefix is always 254.Dq Li kernel: . 255.It Fl p 256Specify the pathname of an alternate log socket to be used instead; 257the default is 258.Pa /var/run/log . 259.It Fl P 260Specify an alternative file in which to store the process ID. 261The default is 262.Pa /var/run/syslog.pid . 263.It Fl S 264Specify the pathname of an alternate log socket for privileged 265applications to be used instead; the default is 266.Pa /var/run/logpriv . 267.It Fl l 268Specify a location where 269.Nm 270should place an additional log socket. 271The primary use for this is to place additional log sockets in 272.Pa /var/run/log 273of various chroot filespaces. 274File permissions for socket can be specified in octal representation 275before socket name, delimited with a colon. 276Path to socket location must be absolute. 277.It Fl s 278Operate in secure mode. 279Do not log messages from remote machines. 280If 281specified twice, no network socket will be opened at all, which also 282disables logging to remote machines. 283.It Fl T 284Always use the local time and date for messages received from the network, 285instead of the timestamp field supplied in the message by the remote host. 286This is useful if some of the originating hosts can't keep time properly 287or are unable to generate a correct timestamp. 288.It Fl u 289Unique priority logging. 290Only log messages at the specified priority. 291Without this option, messages at the stated priority or higher are logged. 292This option changes the default comparison from 293.Dq => 294to 295.Dq = . 296.It Fl v 297Verbose logging. 298If specified once, the numeric facility and priority are 299logged with each locally-written message. 300If specified more than once, 301the names of the facility and priority are logged with each locally-written 302message. 303.El 304.Pp 305The 306.Nm 307utility reads its configuration file when it starts up and whenever it 308receives a hangup signal. 309For information on the format of the configuration file, 310see 311.Xr syslog.conf 5 . 312.Pp 313The 314.Nm 315utility reads messages from the 316.Ux 317domain sockets 318.Pa /var/run/log 319and 320.Pa /var/run/logpriv , 321from an Internet domain socket specified in 322.Pa /etc/services , 323and from the special device 324.Pa /dev/klog 325(to read kernel messages). 326.Pp 327The 328.Nm 329utility creates its process ID file, 330by default 331.Pa /var/run/syslog.pid , 332and stores its process 333ID there. 334This can be used to kill or reconfigure 335.Nm . 336.Pp 337The message sent to 338.Nm 339should consist of a single line. 340The message can contain a priority code, which should be a preceding 341decimal number in angle braces, for example, 342.Sq Aq 5 . 343This priority code should map into the priorities defined in the 344include file 345.In sys/syslog.h . 346.Pp 347For security reasons, 348.Nm 349will not append to log files that do not exist (unless 350.Fl C 351option is specified); 352therefore, they must be created manually before running 353.Nm . 354.Pp 355The date and time are taken from the received message. 356If the format of the timestamp field is incorrect, 357time obtained from the local host is used instead. 358This can be overridden by the 359.Fl T 360flag. 361.Sh FILES 362.Bl -tag -width /var/run/syslog.pid -compact 363.It Pa /etc/syslog.conf 364configuration file 365.It Pa /var/run/syslog.pid 366default process ID file 367.It Pa /var/run/log 368name of the 369.Ux 370domain datagram log socket 371.It Pa /var/run/logpriv 372.Ux 373socket for privileged applications 374.It Pa /dev/klog 375kernel log device 376.El 377.Sh SEE ALSO 378.Xr logger 1 , 379.Xr syslog 3 , 380.Xr services 5 , 381.Xr syslog.conf 5 , 382.Xr newsyslog 8 383.Sh HISTORY 384The 385.Nm 386utility appeared in 387.Bx 4.3 . 388.Pp 389The 390.Fl a , 391.Fl s , 392.Fl u , 393and 394.Fl v 395options are 396.Fx 2.2 397extensions. 398.Sh BUGS 399The ability to log messages received in UDP packets is equivalent to 400an unauthenticated remote disk-filling service, and should probably be 401disabled by default. 402Some sort of 403.No inter- Ns Nm syslogd 404authentication mechanism ought to be worked out. 405To prevent the worst 406abuse, use of the 407.Fl a 408option is therefore highly recommended. 409.Pp 410The 411.Fl a 412matching algorithm does not pretend to be very efficient; use of numeric 413IP addresses is faster than domain name comparison. 414Since the allowed 415peer list is being walked linearly, peer groups where frequent messages 416are being anticipated from should be put early into the 417.Fl a 418list. 419.Pp 420The log socket was moved from 421.Pa /dev 422to ease the use of a read-only root file system. 423This may confuse 424some old binaries so that a symbolic link might be used for a 425transitional period. 426