1.\" -*- tab-width: 4 -*- 2.\" 3.\" Copyright (c) 2003-2004 Apple Computer, Inc. All Rights Reserved. 4.\" 5.\" Licensed under the Apache License, Version 2.0 (the "License"); 6.\" you may not use this file except in compliance with the License. 7.\" You may obtain a copy of the License at 8.\" 9.\" http://www.apache.org/licenses/LICENSE-2.0 10.\" 11.\" Unless required by applicable law or agreed to in writing, software 12.\" distributed under the License is distributed on an "AS IS" BASIS, 13.\" WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14.\" See the License for the specific language governing permissions and 15.\" limitations under the License. 16.\" 17.\" Log: mDNSResponder.8,v $ 18.\" Revision 1.10 2009/04/20 16:12:13 mcguire 19.\" <rdar://problem/6807798> manpage: roff errors 20.\" 21.\" Revision 1.9 2009/04/11 00:20:27 jessic2 22.\" <rdar://problem/4426780> Daemon: Should be able to turn on LogOperation dynamically 23.\" 24.\" Revision 1.8 2006/10/06 17:31:33 mkrochma 25.\" <rdar://problem/4769407> Typo in man page for mDNSResponder(8) 26.\" 27.\" Revision 1.7 2006/08/14 23:24:56 cheshire 28.\" Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0 29.\" 30.\" Revision 1.6 2005/02/10 22:35:28 cheshire 31.\" <rdar://problem/3727944> Update name 32.\" 33.\" Revision 1.5 2004/06/29 02:41:38 cheshire 34.\" Add note that mDNSResponder is called mdnsd on some systems 35.\" 36.\" Revision 1.4 2004/05/18 18:14:36 cheshire 37.\" Minor wording update 38.\" 39.\" Revision 1.3 2004/04/22 02:56:08 cheshire 40.\" <rdar://problem/3619494>: mDNSResponder man page format error 41.\" 42.\" Revision 1.2 2004/04/12 18:03:24 ksekar 43.\" <rdar://problem/3619494>: mDNSResponder man page format error 44.\" 45.\" Revision 1.1 2003/11/13 03:21:38 cheshire 46.\" <rdar://problem/3086886>: No man page for mDNSResponder 47.\" 48.\" 49.\" 50.Dd April 2004 \" Date 51.Dt mDNSResponder 8 \" Document Title 52.Os Darwin \" Operating System 53.\" 54.Sh NAME 55.Nm mDNSResponder 56.Nd Multicast and Unicast DNS daemon \" Name Description for whatis database 57.\" 58.Sh SYNOPSIS 59.Nm 60.\" 61.Sh DESCRIPTION 62.Nm 63(also known as 64.Nm mdnsd 65on some systems) 66is a daemon invoked at boot time to implement Multicast DNS and DNS Service Discovery. On 67Mac OS X 10.6 (Snow Leopard), 68.Nm 69is also the system-wide Unicast DNS Resolver. 70.Pp 71.Nm 72listens on UDP port 5353 for Multicast DNS Query packets. 73When it receives a query for which it knows an answer, 74.Nm 75issues the appropriate Multicast DNS Reply packet. 76.Pp 77.Nm 78also performs Unicast and Multicast DNS Queries on behalf of client processes, and 79maintains a cache of the replies. 80.Pp 81.Nm 82has no user-specifiable command-line argument, and users should not run 83.Nm 84manually. 85.Pp 86.Ss LOGGING 87There are several methods with which to examine 88.Nm Ns 's internal state for debugging and diagnostic purposes. The syslog(1) 89logging levels map as follows: 90.Pp 91.Dl Error - Error messages 92.Dl Warning - Client-initiated operations 93.Dl Notice - Sleep proxy operations 94.Dl Info - Informational messages 95.Pp 96By default, only log level Error is logged. 97.Pp 98A SIGUSR1 signal toggles additional logging, with Warning and Notice 99enabled by default: 100.Pp 101.Dl % sudo killall -USR1 mDNSResponder 102.Pp 103Once this logging is enabled, users can additionally use syslog(1) 104to change the log filter for the process. For example, to enable log levels Emergency - Debug: 105.Pp 106.Dl % sudo syslog -c mDNSResponder -d 107.Pp 108A SIGUSR2 signal toggles packet logging: 109.Pp 110.Dl % sudo killall -USR2 mDNSResponder 111.Pp 112A SIGINFO signal will dump a snapshot summary of the internal state to 113.Pa /var/log/system.log Ns : 114.Pp 115.Dl % sudo killall -INFO mDNSResponder 116.Sh FILES 117.Pa /usr/sbin/mDNSResponder \" Pathname 118.\" 119.Sh SEE ALSO 120.Xr mDNS 1 121.Pp 122For information on Multicast DNS, see 123.Pa http://www.multicastdns.org/ 124.Pp 125For information on DNS Service Discovery, see 126.Pa http://www.dns-sd.org/ 127.Pp 128For information on how to use the Multicast DNS and the 129DNS Service Discovery APIs on Mac OS X and other platforms, see 130.Pa http://developer.apple.com/bonjour/ 131.Pp 132For the source code to 133.Nm , see 134.Pa http://developer.apple.com/darwin/projects/bonjour/ 135.\" 136.Sh BUGS 137.Nm 138bugs are tracked in Apple Radar component "mDNSResponder". 139.\" 140.Sh HISTORY 141The 142.Nm 143daemon first appeared in Mac OS X 10.2 (Jaguar). 144.Pp 145Also available from the Darwin open source repository 146(though not officially supported by Apple) are 147.Nm 148daemons for other platforms, including Mac OS 9, Microsoft Windows, 149Linux, FreeBSD, NetBSD, Solaris, and other POSIX systems. 150