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 October 12, 1995 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 46Adknsuv 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 p 185Specify the pathname of an alternate log socket to be used instead; 186the default is 187.Pa /var/run/log . 188.It Fl P 189Specify an alternative file in which to store the process ID. 190The default is 191.Pa /var/run/syslog.pid . 192.It Fl l 193Specify a location where 194.Nm 195should place an additional log socket. 196Up to 19 additional logging sockets can be specified. 197The primary use for this is to place additional log sockets in 198.Pa /var/run/log 199of various chroot filespaces. 200.It Fl s 201Operate in secure mode. Do not log messages from remote machines. If 202specified twice, no network socket will be opened at all, which also 203disables logging to remote machines. 204.It Fl u 205Unique priority logging. Only log messages at the specified priority. 206Without this option, messages at the stated priority or higher are logged. 207This option changes the default comparison from 208.Dq => 209to 210.Dq = . 211.It Fl v 212Verbose logging. If specified once, the numeric facility and priority are 213logged with each locally-written message. If specified more than once, 214the names of the facility and priority are logged with each locally-written 215message. 216.El 217.Pp 218The 219.Nm 220daemon reads its configuration file when it starts up and whenever it 221receives a hangup signal. 222For information on the format of the configuration file, 223see 224.Xr syslog.conf 5 . 225.Pp 226The 227.Nm 228daemon reads messages from the 229.Tn UNIX 230domain socket 231.Pa /var/run/log , 232from an Internet domain socket specified in 233.Pa /etc/services , 234and from the special device 235.Pa /dev/klog 236(to read kernel messages). 237.Pp 238The 239.Nm 240daemon creates its process ID file, 241by default 242.Pa /var/run/syslog.pid , 243and stores its process 244ID there. 245This can be used to kill or reconfigure 246.Nm . 247.Pp 248The message sent to 249.Nm 250should consist of a single line. 251The message can contain a priority code, which should be a preceding 252decimal number in angle braces, for example, 253.Sq Aq 5 . 254This priority code should map into the priorities defined in the 255include file 256.Aq Pa sys/syslog.h . 257.Pp 258For security reasons, 259.Nm 260will not append to log files that do not exist; 261therefore, they must be created manually before running 262.Nm . 263.Sh FILES 264.Bl -tag -width /var/run/syslog.pid -compact 265.It Pa /etc/syslog.conf 266configuration file 267.It Pa /var/run/syslog.pid 268default process ID file 269.It Pa /var/run/log 270name of the 271.Tn UNIX 272domain datagram log socket 273.It Pa /dev/klog 274kernel log device 275.El 276.Sh SEE ALSO 277.Xr logger 1 , 278.Xr syslog 3 , 279.Xr services 5 , 280.Xr syslog.conf 5 281.Sh HISTORY 282The 283.Nm 284command appeared in 285.Bx 4.3 . 286.Pp 287The 288.Fl a , 289.Fl s , 290.Fl u , 291and 292.Fl v 293options are 294.Fx 2.2 295extensions. 296.Sh BUGS 297The ability to log messages received in UDP packets is equivalent to 298an unauthenticated remote disk-filling service, and should probably be 299disabled by default. Some sort of 300.No inter- Ns Nm syslogd 301authentication mechanism ought to be worked out. To prevent the worst 302abuse, use of the 303.Fl a 304option is therefore highly recommended. 305.Pp 306The 307.Fl a 308matching algorithm doesn't pretend to be very efficient; use of numeric 309IP addresses is faster than domain name comparison. Since the allowed 310peer list is being walked linearly, peer groups where frequent messages 311are being anticipated from should be put early into the 312.Fl a 313list. 314.Pp 315The log socket was moved from 316.Pa /dev 317to ease the use of a read-only root filesystem. 318This may confuse 319some old binaries so that a symbolic link might be used for a 320transitional period. 321