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 46Adknosuv 44.Op Fl a Ar allowed_peer 45.Op Fl b Ar bind_address 46.Op Fl f Ar config_file 47.Op Fl m Ar mark_interval 48.Op Fl p Ar log_socket 49.Op Fl P Ar pid_file 50.Op Fl l Ar path 51.Sh DESCRIPTION 52The 53.Nm 54daemon 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 60Forces 61.Nm 62to use IPv4 addresses only. 63.It Fl 6 64Forces 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 d 160Put 161.Nm 162into debugging mode. This is probably only of use to developers working on 163.Nm . 164.It Fl f 165Specify the pathname of an alternate configuration file; 166the default is 167.Pa /etc/syslog.conf . 168.It Fl k 169Disable the translation of 170messages received with facility 171.Dq kern 172to facility 173.Dq user . 174Usually the 175.Dq kern 176facility is reserved for messages read directly from 177.Pa /dev/klog . 178.It Fl m 179Select the number of minutes between 180.Dq mark 181messages; the default is 20 minutes. 182.It Fl n 183Disable dns query for every request. 184.It Fl o 185Prefix kernel messages with the full kernel boot file as determined by 186.Xr getbootfile 3 . 187Without this, the kernel message prefix is always 188.Dq kernel: . 189.It Fl p 190Specify the pathname of an alternate log socket to be used instead; 191the default is 192.Pa /var/run/log . 193.It Fl P 194Specify an alternative file in which to store the process ID. 195The default is 196.Pa /var/run/syslog.pid . 197.It Fl l 198Specify a location where 199.Nm 200should place an additional log socket. 201Up to 19 additional logging sockets can be specified. 202The primary use for this is to place additional log sockets in 203.Pa /var/run/log 204of various chroot filespaces. 205.It Fl s 206Operate in secure mode. Do not log messages from remote machines. If 207specified twice, no network socket will be opened at all, which also 208disables logging to remote machines. 209.It Fl u 210Unique priority logging. Only log messages at the specified priority. 211Without this option, messages at the stated priority or higher are logged. 212This option changes the default comparison from 213.Dq => 214to 215.Dq = . 216.It Fl v 217Verbose logging. If specified once, the numeric facility and priority are 218logged with each locally-written message. If specified more than once, 219the names of the facility and priority are logged with each locally-written 220message. 221.El 222.Pp 223The 224.Nm 225daemon reads its configuration file when it starts up and whenever it 226receives a hangup signal. 227For information on the format of the configuration file, 228see 229.Xr syslog.conf 5 . 230.Pp 231The 232.Nm 233daemon reads messages from the 234.Tn UNIX 235domain socket 236.Pa /var/run/log , 237from an Internet domain socket specified in 238.Pa /etc/services , 239and from the special device 240.Pa /dev/klog 241(to read kernel messages). 242.Pp 243The 244.Nm 245daemon creates its process ID file, 246by default 247.Pa /var/run/syslog.pid , 248and stores its process 249ID there. 250This can be used to kill or reconfigure 251.Nm . 252.Pp 253The message sent to 254.Nm 255should consist of a single line. 256The message can contain a priority code, which should be a preceding 257decimal number in angle braces, for example, 258.Sq Aq 5 . 259This priority code should map into the priorities defined in the 260include file 261.Aq Pa sys/syslog.h . 262.Pp 263For security reasons, 264.Nm 265will not append to log files that do not exist; 266therefore, they must be created manually before running 267.Nm . 268.Sh FILES 269.Bl -tag -width /var/run/syslog.pid -compact 270.It Pa /etc/syslog.conf 271configuration file 272.It Pa /var/run/syslog.pid 273default process ID file 274.It Pa /var/run/log 275name of the 276.Tn UNIX 277domain datagram log socket 278.It Pa /dev/klog 279kernel log device 280.El 281.Sh SEE ALSO 282.Xr logger 1 , 283.Xr syslog 3 , 284.Xr services 5 , 285.Xr syslog.conf 5 286.Sh HISTORY 287The 288.Nm 289command appeared in 290.Bx 4.3 . 291.Pp 292The 293.Fl a , 294.Fl s , 295.Fl u , 296and 297.Fl v 298options are 299.Fx 2.2 300extensions. 301.Sh BUGS 302The ability to log messages received in UDP packets is equivalent to 303an unauthenticated remote disk-filling service, and should probably be 304disabled by default. Some sort of 305.No inter- Ns Nm syslogd 306authentication mechanism ought to be worked out. To prevent the worst 307abuse, use of the 308.Fl a 309option is therefore highly recommended. 310.Pp 311The 312.Fl a 313matching algorithm doesn't pretend to be very efficient; use of numeric 314IP addresses is faster than domain name comparison. Since the allowed 315peer list is being walked linearly, peer groups where frequent messages 316are being anticipated from should be put early into the 317.Fl a 318list. 319.Pp 320The log socket was moved from 321.Pa /dev 322to ease the use of a read-only root filesystem. 323This may confuse 324some old binaries so that a symbolic link might be used for a 325transitional period. 326