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 November 8, 2004 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 46Acdknosuv 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 A 64Ordinarily, 65.Nm 66tries to send the message to only one address 67even if the host has more than one A or AAAA record. 68If this option is specified, 69.Nm 70tries to send the message to all addresses. 71.It Fl a Ar allowed_peer 72Allow 73.Ar allowed_peer 74to log to this 75.Nm 76using UDP datagrams. 77Multiple 78.Fl a 79options may be specified. 80.Pp 81.Ar Allowed_peer 82can be any of the following: 83.Bl -tag -width "ipaddr/masklen[:service]XX" 84.It Xo 85.Sm off 86.Ar ipaddr 87.No / Ar masklen 88.Op : Ar service 89.Sm on 90.Xc 91Accept datagrams from 92.Ar ipaddr 93(in the usual dotted quad notation) with 94.Ar masklen 95bits being taken into account when doing the address comparison. 96.Ar ipaddr 97can be also IPv6 address by enclosing the address with 98.Ql \&[ 99and 100.Ql \&] . 101If specified, 102.Ar service 103is the name or number of an UDP service (see 104.Xr services 5 ) 105the source packet must belong to. 106A 107.Ar service 108of 109.Ql \&* 110allows packets being sent from any UDP port. 111The default 112.Ar service 113is 114.Ql syslog . 115If 116.Ar ipaddr 117is IPv4 address, a missing 118.Ar masklen 119will be substituted by the historic class A or class B netmasks if 120.Ar ipaddr 121belongs into the address range of class A or B, respectively, or 122by 24 otherwise. 123If 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. 136The meaning of 137.Ar service 138is as explained above. 139.It Xo 140.Sm off 141.No * Ar domainname Op : Ar service 142.Sm on 143.Xc 144Same as before, except that any source host whose name 145.Em ends 146in 147.Ar domainname 148will get permission. 149.El 150.Pp 151The 152.Fl a 153options are ignored if the 154.Fl s 155option is also specified. 156.It Fl b Ar bind_address 157Specify one specific IP address or hostname to bind to. 158If a hostname is specified, 159the IPv4 or IPv6 address which corresponds to it is used. 160.It Fl c 161Disable the compression of repeated instances of the same line 162into a single line of the form 163.Dq Li "last message repeated N times" 164when the output is a pipe to another program. 165If specified twice, disable this compression in all cases. 166.It Fl d 167Put 168.Nm 169into debugging mode. 170This is probably only of use to developers working on 171.Nm . 172.It Fl f 173Specify the pathname of an alternate configuration file; 174the default is 175.Pa /etc/syslog.conf . 176.It Fl k 177Disable the translation of 178messages received with facility 179.Dq kern 180to facility 181.Dq user . 182Usually the 183.Dq kern 184facility is reserved for messages read directly from 185.Pa /dev/klog . 186.It Fl m 187Select the number of minutes between 188.Dq mark 189messages; the default is 20 minutes. 190.It Fl n 191Disable dns query for every request. 192.It Fl o 193Prefix kernel messages with the full kernel boot file as determined by 194.Xr getbootfile 3 . 195Without this, the kernel message prefix is always 196.Dq Li kernel: . 197.It Fl p 198Specify the pathname of an alternate log socket to be used instead; 199the default is 200.Pa /var/run/log . 201.It Fl P 202Specify an alternative file in which to store the process ID. 203The default is 204.Pa /var/run/syslog.pid . 205.It Fl l 206Specify a location where 207.Nm 208should place an additional log socket. 209The primary use for this is to place additional log sockets in 210.Pa /var/run/log 211of various chroot filespaces. 212File permissions for socket can be specified in octal representation 213before socket name, delimited with a colon. 214Path to socket location must be absolute. 215.It Fl s 216Operate in secure mode. 217Do not log messages from remote machines. 218If 219specified twice, no network socket will be opened at all, which also 220disables logging to remote machines. 221.It Fl u 222Unique priority logging. 223Only log messages at the specified priority. 224Without this option, messages at the stated priority or higher are logged. 225This option changes the default comparison from 226.Dq => 227to 228.Dq = . 229.It Fl v 230Verbose logging. 231If specified once, the numeric facility and priority are 232logged with each locally-written message. 233If specified more than once, 234the names of the facility and priority are logged with each locally-written 235message. 236.El 237.Pp 238The 239.Nm 240utility reads its configuration file when it starts up and whenever it 241receives a hangup signal. 242For information on the format of the configuration file, 243see 244.Xr syslog.conf 5 . 245.Pp 246The 247.Nm 248utility reads messages from the 249.Ux 250domain sockets 251.Pa /var/run/log 252and 253.Pa /var/run/logpriv , 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 /var/run/logpriv 296.Ux 297socket for privileged applications 298.It Pa /dev/klog 299kernel log device 300.El 301.Sh SEE ALSO 302.Xr logger 1 , 303.Xr syslog 3 , 304.Xr services 5 , 305.Xr syslog.conf 5 , 306.Xr newsyslog 8 307.Sh HISTORY 308The 309.Nm 310utility appeared in 311.Bx 4.3 . 312.Pp 313The 314.Fl a , 315.Fl s , 316.Fl u , 317and 318.Fl v 319options are 320.Fx 2.2 321extensions. 322.Sh BUGS 323The ability to log messages received in UDP packets is equivalent to 324an unauthenticated remote disk-filling service, and should probably be 325disabled by default. 326Some sort of 327.No inter- Ns Nm syslogd 328authentication mechanism ought to be worked out. 329To prevent the worst 330abuse, use of the 331.Fl a 332option is therefore highly recommended. 333.Pp 334The 335.Fl a 336matching algorithm does not pretend to be very efficient; use of numeric 337IP addresses is faster than domain name comparison. 338Since the allowed 339peer list is being walked linearly, peer groups where frequent messages 340are being anticipated from should be put early into the 341.Fl a 342list. 343.Pp 344The log socket was moved from 345.Pa /dev 346to ease the use of a read-only root file system. 347This may confuse 348some old binaries so that a symbolic link might be used for a 349transitional period. 350