| .\" -*- tab-width: 4 -*- |
| .\" |
| .\" Copyright (c) 2003-2004 Apple Computer, Inc. All Rights Reserved. |
| .\" |
| .\" Licensed under the Apache License, Version 2.0 (the "License"); |
| .\" you may not use this file except in compliance with the License. |
| .\" You may obtain a copy of the License at |
| .\" |
| .\" http://www.apache.org/licenses/LICENSE-2.0 |
| .\" |
| .\" Unless required by applicable law or agreed to in writing, software |
| .\" distributed under the License is distributed on an "AS IS" BASIS, |
| .\" WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| .\" See the License for the specific language governing permissions and |
| .\" limitations under the License. |
| .\" |
| .Dd April 2004 \" Date |
| .Dt mDNSResponder 8 \" Document Title |
| .Os Darwin \" Operating System |
| .\" |
| .Sh NAME |
| .Nm mDNSResponder |
| .Nd Multicast and Unicast DNS daemon \" Name Description for whatis database |
| .\" |
| .Sh SYNOPSIS |
| .Nm |
| .\" |
| .Sh DESCRIPTION |
| .Nm |
| (also known as |
| .Nm mdnsd |
| on some systems) |
| is a daemon invoked at boot time to implement Multicast DNS and DNS Service Discovery. On |
| Mac OS X 10.6 (Snow Leopard), |
| .Nm |
| is also the system-wide Unicast DNS Resolver. |
| .Pp |
| .Nm |
| listens on UDP port 5353 for Multicast DNS Query packets. |
| When it receives a query for which it knows an answer, |
| .Nm |
| issues the appropriate Multicast DNS Reply packet. |
| .Pp |
| .Nm |
| also performs Unicast and Multicast DNS Queries on behalf of client processes, and |
| maintains a cache of the replies. |
| .Pp |
| .Nm |
| has no user-specifiable command-line argument, and users should not run |
| .Nm |
| manually. |
| .Pp |
| .Ss LOGGING |
| There are several methods with which to examine |
| .Nm Ns 's internal state for debugging and diagnostic purposes. The syslog(1) |
| logging levels map as follows: |
| .Pp |
| .Dl Error - Error messages |
| .Dl Warning - Client-initiated operations |
| .Dl Notice - Sleep proxy operations |
| .Dl Info - Informational messages |
| .Pp |
| By default, only log level Error is logged. |
| .Pp |
| A SIGUSR1 signal toggles additional logging, with Warning and Notice |
| enabled by default: |
| .Pp |
| .Dl % sudo killall -USR1 mDNSResponder |
| .Pp |
| Once this logging is enabled, users can additionally use syslog(1) |
| to change the log filter for the process. For example, to enable log levels Emergency - Debug: |
| .Pp |
| .Dl % sudo syslog -c mDNSResponder -d |
| .Pp |
| A SIGUSR2 signal toggles packet logging: |
| .Pp |
| .Dl % sudo killall -USR2 mDNSResponder |
| .Pp |
| A SIGINFO signal will dump a snapshot summary of the internal state to |
| .Pa /var/log/system.log Ns : |
| .Pp |
| .Dl % sudo killall -INFO mDNSResponder |
| .Sh FILES |
| .Pa /usr/sbin/mDNSResponder \" Pathname |
| .\" |
| .Sh SEE ALSO |
| .Xr mDNS 1 |
| .Pp |
| For information on Multicast DNS, see |
| .Pa http://www.multicastdns.org/ |
| .Pp |
| For information on DNS Service Discovery, see |
| .Pa http://www.dns-sd.org/ |
| .Pp |
| For information on how to use the Multicast DNS and the |
| DNS Service Discovery APIs on Mac OS X and other platforms, see |
| .Pa http://developer.apple.com/bonjour/ |
| .Pp |
| For the source code to |
| .Nm , see |
| .Pa http://developer.apple.com/darwin/projects/bonjour/ |
| .\" |
| .Sh BUGS |
| .Nm |
| bugs are tracked in Apple Radar component "mDNSResponder". |
| .\" |
| .Sh HISTORY |
| The |
| .Nm |
| daemon first appeared in Mac OS X 10.2 (Jaguar). |
| .Pp |
| Also available from the Darwin open source repository |
| (though not officially supported by Apple) are |
| .Nm |
| daemons for other platforms, including Mac OS 9, Microsoft Windows, |
| Linux, FreeBSD, NetBSD, Solaris, and other POSIX systems. |
