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.Dd April 2004 \" Date 18.Dt mDNSResponder 8 \" Document Title 19.Os Darwin \" Operating System 20.\" 21.Sh NAME 22.Nm mDNSResponder 23.Nd Multicast and Unicast DNS daemon \" Name Description for whatis database 24.\" 25.Sh SYNOPSIS 26.Nm 27.\" 28.Sh DESCRIPTION 29.Nm 30(also known as 31.Nm mdnsd 32on some systems) 33is a daemon invoked at boot time to implement Multicast DNS and DNS Service Discovery. On 34Mac OS X 10.6 (Snow Leopard), 35.Nm 36is also the system-wide Unicast DNS Resolver. 37.Pp 38.Nm 39listens on UDP port 5353 for Multicast DNS Query packets. 40When it receives a query for which it knows an answer, 41.Nm 42issues the appropriate Multicast DNS Reply packet. 43.Pp 44.Nm 45also performs Unicast and Multicast DNS Queries on behalf of client processes, and 46maintains a cache of the replies. 47.Pp 48.Nm 49has no user-specifiable command-line argument, and users should not run 50.Nm 51manually. 52.Pp 53.Ss LOGGING 54There are several methods with which to examine 55.Nm Ns 's internal state for debugging and diagnostic purposes. The syslog(1) 56logging levels map as follows: 57.Pp 58.Dl Error - Error messages 59.Dl Warning - Client-initiated operations 60.Dl Notice - Sleep proxy operations 61.Dl Info - Informational messages 62.Pp 63By default, only log level Error is logged. 64.Pp 65A SIGUSR1 signal toggles additional logging, with Warning and Notice 66enabled by default: 67.Pp 68.Dl % sudo killall -USR1 mDNSResponder 69.Pp 70Once this logging is enabled, users can additionally use syslog(1) 71to change the log filter for the process. For example, to enable log levels Emergency - Debug: 72.Pp 73.Dl % sudo syslog -c mDNSResponder -d 74.Pp 75A SIGUSR2 signal toggles packet logging: 76.Pp 77.Dl % sudo killall -USR2 mDNSResponder 78.Pp 79A SIGINFO signal will dump a snapshot summary of the internal state to 80.Pa /var/log/system.log Ns : 81.Pp 82.Dl % sudo killall -INFO mDNSResponder 83.Sh FILES 84.Pa /usr/sbin/mDNSResponder \" Pathname 85.\" 86.Sh SEE ALSO 87.Xr mDNS 1 88.Pp 89For information on Multicast DNS, see 90.Pa http://www.multicastdns.org/ 91.Pp 92For information on DNS Service Discovery, see 93.Pa http://www.dns-sd.org/ 94.Pp 95For information on how to use the Multicast DNS and the 96DNS Service Discovery APIs on Mac OS X and other platforms, see 97.Pa http://developer.apple.com/bonjour/ 98.Pp 99For the source code to 100.Nm , see 101.Pa http://developer.apple.com/darwin/projects/bonjour/ 102.\" 103.Sh BUGS 104.Nm 105bugs are tracked in Apple Radar component "mDNSResponder". 106.\" 107.Sh HISTORY 108The 109.Nm 110daemon first appeared in Mac OS X 10.2 (Jaguar). 111.Pp 112Also available from the Darwin open source repository 113(though not officially supported by Apple) are 114.Nm 115daemons for other platforms, including Mac OS 9, Microsoft Windows, 116Linux, FreeBSD, NetBSD, Solaris, and other POSIX systems. 117