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. 81Multiple 82.Fl a 83options may be specified. 84.Pp 85.Ar Allowed_peer 86can be any of the following: 87.Bl -tag -width "ipaddr/masklen[:service]XX" 88.It Xo 89.Sm off 90.Ar ipaddr 91.No / Ar masklen 92.Op : Ar service 93.Sm on 94.Xc 95Accept datagrams from 96.Ar ipaddr 97(in the usual dotted quad notation) with 98.Ar masklen 99bits being taken into account when doing the address comparison. 100.Ar ipaddr 101can be also IPv6 address by enclosing the address with 102.Ql \&[ 103and 104.Ql \&] . 105If specified, 106.Ar service 107is the name or number of an UDP service (see 108.Xr services 5 ) 109the source packet must belong to. 110A 111.Ar service 112of 113.Ql \&* 114allows packets being sent from any UDP port. 115The default 116.Ar service 117is 118.Ql syslog . 119If 120.Ar ipaddr 121is IPv4 address, a missing 122.Ar masklen 123will be substituted by the historic class A or class B netmasks if 124.Ar ipaddr 125belongs into the address range of class A or B, respectively, or 126by 24 otherwise. 127If 128.Ar ipaddr 129is IPv6 address, a missing 130.Ar masklen 131will be substituted by 128. 132.It Xo 133.Sm off 134.Ar domainname Op : Ar service 135.Sm on 136.Xc 137Accept datagrams where the reverse address lookup yields 138.Ar domainname 139for the sender address. 140The meaning of 141.Ar service 142is as explained above. 143.It Xo 144.Sm off 145.No * Ar domainname Op : Ar service 146.Sm on 147.Xc 148Same as before, except that any source host whose name 149.Em ends 150in 151.Ar domainname 152will get permission. 153.El 154.Pp 155The 156.Fl a 157options are ignored if the 158.Fl s 159option is also specified. 160.It Fl b Ar bind_address 161Specify one specific IP address or hostname to bind to. 162If a hostname is specified, 163the IPv4 or IPv6 address which corresponds to it is used. 164.It Fl c 165Disable the compression of repeated instances of the same line 166into a single line of the form 167.Dq Li "last message repeated N times" 168when the output is a pipe to another program. 169If specified twice, disable this compression in all cases. 170.It Fl d 171Put 172.Nm 173into debugging mode. 174This is probably only of use to developers working on 175.Nm . 176.It Fl f 177Specify the pathname of an alternate configuration file; 178the default is 179.Pa /etc/syslog.conf . 180.It Fl k 181Disable the translation of 182messages received with facility 183.Dq kern 184to facility 185.Dq user . 186Usually the 187.Dq kern 188facility is reserved for messages read directly from 189.Pa /dev/klog . 190.It Fl m 191Select the number of minutes between 192.Dq mark 193messages; the default is 20 minutes. 194.It Fl n 195Disable dns query for every request. 196.It Fl o 197Prefix kernel messages with the full kernel boot file as determined by 198.Xr getbootfile 3 . 199Without this, the kernel message prefix is always 200.Dq Li kernel: . 201.It Fl p 202Specify the pathname of an alternate log socket to be used instead; 203the default is 204.Pa /var/run/log . 205.It Fl P 206Specify an alternative file in which to store the process ID. 207The default is 208.Pa /var/run/syslog.pid . 209.It Fl l 210Specify a location where 211.Nm 212should place an additional log socket. 213Up to 19 additional logging sockets can be specified. 214The primary use for this is to place additional log sockets in 215.Pa /var/run/log 216of various chroot filespaces. 217.It Fl s 218Operate in secure mode. 219Do not log messages from remote machines. 220If 221specified twice, no network socket will be opened at all, which also 222disables logging to remote machines. 223.It Fl u 224Unique priority logging. 225Only log messages at the specified priority. 226Without this option, messages at the stated priority or higher are logged. 227This option changes the default comparison from 228.Dq => 229to 230.Dq = . 231.It Fl v 232Verbose logging. 233If specified once, the numeric facility and priority are 234logged with each locally-written message. 235If specified more than once, 236the names of the facility and priority are logged with each locally-written 237message. 238.El 239.Pp 240The 241.Nm 242utility reads its configuration file when it starts up and whenever it 243receives a hangup signal. 244For information on the format of the configuration file, 245see 246.Xr syslog.conf 5 . 247.Pp 248The 249.Nm 250utility reads messages from the 251.Ux 252domain socket 253.Pa /var/run/log , 254from an Internet domain socket specified in 255.Pa /etc/services , 256and from the special device 257.Pa /dev/klog 258(to read kernel messages). 259.Pp 260The 261.Nm 262utility creates its process ID file, 263by default 264.Pa /var/run/syslog.pid , 265and stores its process 266ID there. 267This can be used to kill or reconfigure 268.Nm . 269.Pp 270The message sent to 271.Nm 272should consist of a single line. 273The message can contain a priority code, which should be a preceding 274decimal number in angle braces, for example, 275.Sq Aq 5 . 276This priority code should map into the priorities defined in the 277include file 278.In sys/syslog.h . 279.Pp 280For security reasons, 281.Nm 282will not append to log files that do not exist; 283therefore, they must be created manually before running 284.Nm . 285.Sh FILES 286.Bl -tag -width /var/run/syslog.pid -compact 287.It Pa /etc/syslog.conf 288configuration file 289.It Pa /var/run/syslog.pid 290default process ID file 291.It Pa /var/run/log 292name of the 293.Ux 294domain datagram log socket 295.It Pa /dev/klog 296kernel log device 297.El 298.Sh SEE ALSO 299.Xr logger 1 , 300.Xr syslog 3 , 301.Xr services 5 , 302.Xr syslog.conf 5 303.Sh HISTORY 304The 305.Nm 306utility appeared in 307.Bx 4.3 . 308.Pp 309The 310.Fl a , 311.Fl s , 312.Fl u , 313and 314.Fl v 315options are 316.Fx 2.2 317extensions. 318.Sh BUGS 319The ability to log messages received in UDP packets is equivalent to 320an unauthenticated remote disk-filling service, and should probably be 321disabled by default. 322Some sort of 323.No inter- Ns Nm syslogd 324authentication mechanism ought to be worked out. 325To prevent the worst 326abuse, use of the 327.Fl a 328option is therefore highly recommended. 329.Pp 330The 331.Fl a 332matching algorithm doesn't pretend to be very efficient; use of numeric 333IP addresses is faster than domain name comparison. 334Since the allowed 335peer list is being walked linearly, peer groups where frequent messages 336are being anticipated from should be put early into the 337.Fl a 338list. 339.Pp 340The log socket was moved from 341.Pa /dev 342to ease the use of a read-only root file system. 343This may confuse 344some old binaries so that a symbolic link might be used for a 345transitional period. 346