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.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)syslogd.8 8.1 (Berkeley) 6/6/93 33.\" $FreeBSD$ 34.\" 35.Dd November 24, 2001 36.Dt SYSLOGD 8 37.Os 38.Sh NAME 39.Nm syslogd 40.Nd log systems messages 41.Sh SYNOPSIS 42.Nm 43.Op Fl 46Acdknosuv 44.Op Fl a Ar allowed_peer 45.Op Fl b Ar bind_address 46.Op Fl f Ar config_file 47.Op Fl l Ar path 48.Op Fl m Ar mark_interval 49.Op Fl P Ar pid_file 50.Op Fl p Ar log_socket 51.Sh DESCRIPTION 52The 53.Nm 54utility reads and logs messages to the system console, log files, other 55machines and/or users as specified by its configuration file. 56.Pp 57The options are as follows: 58.Bl -tag -width indent 59.It Fl 4 60Force 61.Nm 62to use IPv4 addresses only. 63.It Fl 6 64Force 65.Nm 66to use IPv6 addresses only. 67.It Fl A 68Ordinarily, 69.Nm 70tries to send the message to only one address 71even if the host has more than one A or AAAA record. 72If this option is specified, 73.Nm 74tries to send the message to all addresses. 75.It Fl a Ar allowed_peer 76Allow 77.Ar allowed_peer 78to log to this 79.Nm 80using UDP datagrams. Multiple 81.Fl a 82options may be specified. 83.Pp 84.Ar Allowed_peer 85can be any of the following: 86.Bl -tag -width "ipaddr/masklen[:service]XX" 87.It Xo 88.Sm off 89.Ar ipaddr 90.No / Ar masklen 91.Op : Ar service 92.Sm on 93.Xc 94Accept datagrams from 95.Ar ipaddr 96(in the usual dotted quad notation) with 97.Ar masklen 98bits being taken into account when doing the address comparison. 99.Ar ipaddr 100can be also IPv6 address by enclosing the address with 101.Ql \&[ 102and 103.Ql \&] . 104If specified, 105.Ar service 106is the name or number of an UDP service (see 107.Xr services 5 ) 108the source packet must belong to. A 109.Ar service 110of 111.Ql \&* 112allows packets being sent from any UDP port. The default 113.Ar service 114is 115.Ql syslog . 116If 117.Ar ipaddr 118is IPv4 address, a missing 119.Ar masklen 120will be substituted by the historic class A or class B netmasks if 121.Ar ipaddr 122belongs into the address range of class A or B, respectively, or 123by 24 otherwise. If 124.Ar ipaddr 125is IPv6 address, a missing 126.Ar masklen 127will be substituted by 128. 128.It Xo 129.Sm off 130.Ar domainname Op : Ar service 131.Sm on 132.Xc 133Accept datagrams where the reverse address lookup yields 134.Ar domainname 135for the sender address. The meaning of 136.Ar service 137is as explained above. 138.It Xo 139.Sm off 140.No * Ar domainname Op : Ar service 141.Sm on 142.Xc 143Same as before, except that any source host whose name 144.Em ends 145in 146.Ar domainname 147will get permission. 148.El 149.Pp 150The 151.Fl a 152options are ignored if the 153.Fl s 154option is also specified. 155.It Fl b Ar bind_address 156Specify one specific IP address or hostname to bind to. 157If a hostname is specified, 158the IPv4 or IPv6 address which corresponds to it is used. 159.It Fl c 160Disable the compression of repeated instances of the same line 161into a single line of the form 162.Dq Li "last message repeated N times" 163when the output is a pipe to another program. 164If specified twice, disable this compression in all cases. 165.It Fl d 166Put 167.Nm 168into debugging mode. This is probably only of use to developers working on 169.Nm . 170.It Fl f 171Specify the pathname of an alternate configuration file; 172the default is 173.Pa /etc/syslog.conf . 174.It Fl k 175Disable the translation of 176messages received with facility 177.Dq kern 178to facility 179.Dq user . 180Usually the 181.Dq kern 182facility is reserved for messages read directly from 183.Pa /dev/klog . 184.It Fl m 185Select the number of minutes between 186.Dq mark 187messages; the default is 20 minutes. 188.It Fl n 189Disable dns query for every request. 190.It Fl o 191Prefix kernel messages with the full kernel boot file as determined by 192.Xr getbootfile 3 . 193Without this, the kernel message prefix is always 194.Dq Li kernel: . 195.It Fl p 196Specify the pathname of an alternate log socket to be used instead; 197the default is 198.Pa /var/run/log . 199.It Fl P 200Specify an alternative file in which to store the process ID. 201The default is 202.Pa /var/run/syslog.pid . 203.It Fl l 204Specify a location where 205.Nm 206should place an additional log socket. 207Up to 19 additional logging sockets can be specified. 208The primary use for this is to place additional log sockets in 209.Pa /var/run/log 210of various chroot filespaces. 211.It Fl s 212Operate in secure mode. Do not log messages from remote machines. If 213specified twice, no network socket will be opened at all, which also 214disables logging to remote machines. 215.It Fl u 216Unique priority logging. Only log messages at the specified priority. 217Without this option, messages at the stated priority or higher are logged. 218This option changes the default comparison from 219.Dq => 220to 221.Dq = . 222.It Fl v 223Verbose logging. If specified once, the numeric facility and priority are 224logged with each locally-written message. If specified more than once, 225the names of the facility and priority are logged with each locally-written 226message. 227.El 228.Pp 229The 230.Nm 231utility reads its configuration file when it starts up and whenever it 232receives a hangup signal. 233For information on the format of the configuration file, 234see 235.Xr syslog.conf 5 . 236.Pp 237The 238.Nm 239utility reads messages from the 240.Ux 241domain socket 242.Pa /var/run/log , 243from an Internet domain socket specified in 244.Pa /etc/services , 245and from the special device 246.Pa /dev/klog 247(to read kernel messages). 248.Pp 249The 250.Nm 251utility creates its process ID file, 252by default 253.Pa /var/run/syslog.pid , 254and stores its process 255ID there. 256This can be used to kill or reconfigure 257.Nm . 258.Pp 259The message sent to 260.Nm 261should consist of a single line. 262The message can contain a priority code, which should be a preceding 263decimal number in angle braces, for example, 264.Sq Aq 5 . 265This priority code should map into the priorities defined in the 266include file 267.Aq Pa sys/syslog.h . 268.Pp 269For security reasons, 270.Nm 271will not append to log files that do not exist; 272therefore, they must be created manually before running 273.Nm . 274.Sh FILES 275.Bl -tag -width /var/run/syslog.pid -compact 276.It Pa /etc/syslog.conf 277configuration file 278.It Pa /var/run/syslog.pid 279default process ID file 280.It Pa /var/run/log 281name of the 282.Ux 283domain datagram log socket 284.It Pa /dev/klog 285kernel log device 286.El 287.Sh SEE ALSO 288.Xr logger 1 , 289.Xr syslog 3 , 290.Xr services 5 , 291.Xr syslog.conf 5 292.Sh HISTORY 293The 294.Nm 295utility appeared in 296.Bx 4.3 . 297.Pp 298The 299.Fl a , 300.Fl s , 301.Fl u , 302and 303.Fl v 304options are 305.Fx 2.2 306extensions. 307.Sh BUGS 308The ability to log messages received in UDP packets is equivalent to 309an unauthenticated remote disk-filling service, and should probably be 310disabled by default. Some sort of 311.No inter- Ns Nm syslogd 312authentication mechanism ought to be worked out. To prevent the worst 313abuse, use of the 314.Fl a 315option is therefore highly recommended. 316.Pp 317The 318.Fl a 319matching algorithm doesn't pretend to be very efficient; use of numeric 320IP addresses is faster than domain name comparison. Since the allowed 321peer list is being walked linearly, peer groups where frequent messages 322are being anticipated from should be put early into the 323.Fl a 324list. 325.Pp 326The log socket was moved from 327.Pa /dev 328to ease the use of a read-only root file system. 329This may confuse 330some old binaries so that a symbolic link might be used for a 331transitional period. 332