mDNSShared/dns-sd.1

   1 .\" -*- tab-width: 4 -*-
   2 .\"
   3 .\" Copyright (c) 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: dns-sd.1,v $
  18 .\" Revision 1.6  2006/08/14 23:24:56  cheshire
  19 .\" Re-licensed mDNSResponder daemon source code under Apache License, Version 2.0
  20 .\"
  21 .\" Revision 1.5  2005/07/04 23:12:35  cheshire
  22 .\" <rdar://problem/4103628> The dns-sd command first appeared in Mac OS X 10.4 (Tiger)
  23 .\"
  24 .\" Revision 1.4  2005/02/16 02:29:32  cheshire
  25 .\" Update terminology
  26 .\"
  27 .\" Revision 1.3  2005/02/10 22:35:28  cheshire
  28 .\" <rdar://problem/3727944> Update name
  29 .\"
  30 .\" Revision 1.2  2004/09/24 18:33:05  cheshire
  31 .\" <rdar://problem/3561780> Update man pages to clarify that mDNS and dns-sd are not intended for script use
  32 .\"
  33 .\" Revision 1.1  2004/09/22 22:46:25  cheshire
  34 .\" Man page for dns-sd command-line tool
  35 .\"
  36 .\"
  37 .\"
  38 .Dd April 2004              \" Date
  39 .Dt dns-sd 1                \" Document Title
  40 .Os Darwin                  \" Operating System
  41 .\"
  42 .Sh NAME
  43 .Nm dns-sd
  44 .Nd Multicast DNS (mDNS) & DNS Service Discovery (DNS-SD) Test Tool \" For whatis
  45 .\"
  46 .Sh SYNOPSIS
  47 .Nm Fl R Ar name type domain port Op Ar key=value ...
  48 .Pp
  49 .Nm Fl B Ar      type domain
  50 .Pp
  51 .Nm Fl L Ar name type domain
  52 .\"
  53 .Sh DESCRIPTION
  54 The
  55 .Nm
  56 command is a network diagnostic tool, much like
  57 .Xr ping 8
  58 or
  59 .Xr traceroute 8 .
  60 However, unlike those tools, most of its functionality is not implemented in the
  61 .Nm
  62 executable itself, but in library code that is available to any application.
  63 The library API that
  64 .Nm
  65 uses is documented in
  66 .Pa /usr/include/dns_sd.h .
  67 The
  68 .Nm
  69 command replaces the older
  70 .Xr mDNS 1
  71 command.
  72 .Pp
  73 The
  74 .Nm
  75 command is primarily intended for interactive use.
  76 Because its command-line arguments and output format are subject to change,
  77 invoking it from a shell script will generally be fragile. Additionally,
  78 the asynchronous nature of DNS Service Discovery does
  79 not lend itself easily to script-oriented programming. For example,
  80 calls like "browse" never complete; the action of performing a "browse"
  81 sets in motion machinery to notify the client whenever instances of
  82 that service type appear or disappear from the network. These
  83 notifications continue to be delivered indefinitely, for minutes,
  84 hours, or even days, as services come and go, until the client
  85 explicitly terminates the call. This style of asynchronous interaction
  86 works best with applications that are either multi-threaded, or use a
  87 main event-handling loop to receive keystrokes, network data, and other
  88 asynchronous event notifications as they happen.
  89 .br
  90 If you wish to perform DNS Service Discovery operations from a
  91 scripting language, then the best way to do this is not to execute the
  92 .Nm
  93 command and then attempt to decipher the textual output, but instead to
  94 directly call the DNS-SD APIs using a binding for your chosen language.
  95 .br
  96 For example, if you are programming in Ruby, then you can
  97 directly call DNS-SD APIs using the dnssd package documented at
  98 .Pa <http://rubyforge.org/projects/dnssd/> .
  99 .br
 100 Similar bindings for other languages are also in development.
 101 .Pp
 102 .Bl -tag -width R
 103 .It Nm Fl R Ar name type domain port Op Ar key=value ...
 104 register (advertise) a service in the specified
 105 .Ar domain
 106 with the given
 107 .Ar name
 108 and
 109 .Ar type
 110 as listening (on the current machine) on
 111 .Ar port.
 112 .Pp
 113 .Ar name
 114 can be arbitrary unicode text, containing any legal unicode characters
 115 (including dots, spaces, slashes, colons, etc. without restriction),
 116 up to 63 UTF-8 bytes long.
 117 .Ar type
 118 must be of the form "_app-proto._tcp" or "_app-proto._udp", where
 119 "app-proto" is an application protocol name registered at
 120 .Pa http://www.dns-sd.org/ServiceTypes.html .
 121 .Pp
 122 .Ar domain
 123 is the domain in which to register the service.
 124 In current implementations, only the local multicast domain "local" is
 125 supported. In the future, registering will be supported in any arbitrary
 126 domain that has a working DNS Update server [RFC 2136]. The
 127 .Ar domain
 128 "." is a synonym for "pick a sensible default" which today
 129 means "local".
 130 .Pp
 131 .Ar port
 132 is a number from 0 to 65535, and is the TCP or UDP port number upon
 133 which the service is listening.
 134 .Pp
 135 Additional attributes of the service may optionally be described by
 136 key/value pairs, which are stored in the advertised service's DNS TXT
 137 record. Allowable keys and values are listed with the service
 138 registration at
 139 .Pa http://www.dns-sd.org/ServiceTypes.html .
 140 .It Nm Fl B Ar type domain
 141 browse for instances of service
 142 .Ar type
 143 in
 144 .Ar domain .
 145 .Pp
 146 For valid
 147 .Ar type Ns s
 148 see
 149 .Pa http://www.dns-sd.org/ServiceTypes.html
 150 as described above. Omitting the
 151 .Ar domain
 152 or using "." means "pick a sensible default."
 153 .It Nm Fl L Ar name type domain
 154 look up and display the information necessary to contact and use the
 155 named service: the hostname of the machine where that service is
 156 available, the port number on which the service is listening, and (if
 157 present) TXT record attributes describing properties of the service.
 158 .Pp
 159 Note that in a typical application, browsing happens rarely, while lookup
 160 (or "resolving") happens every time the service is used. For example, a
 161 user browses the network to pick a default printer fairly rarely, but once
 162 a default printer has been picked, that named service is resolved to its
 163 current IP address and port number every time the user presses Cmd-P to
 164 print.
 165 .El
 166 .Sh EXAMPLES
 167 .Pp
 168 To advertise the existence of LPR printing service on port 515 on this
 169 machine, such that it will be discovered by the Mac OS X printing software
 170 and other DNS-SD compatible printing clients, use:
 171 .Pp
 172 .Dl Nm Fl R Ns \ \&"My Test\&" _printer._tcp. \&. 515 pdl=application/postscript
 173 .Pp
 174 For this registration to be useful, you need to actually have LPR service
 175 available on port 515. Advertising a service that does not exist is not
 176 very useful, and will be confusing and annoying to other people on the
 177 network.
 178 .Pp
 179 Similarly, to advertise a web page being served by an HTTP
 180 server on port 80 on this machine, such that it will show up in the
 181 Bonjour list in Safari and other DNS-SD compatible Web clients, use:
 182 .Pp
 183 .Dl Nm Fl R Ns \ \&"My Test\&" _http._tcp \&. 80 path=/path-to-page.html
 184 .Pp
 185 To find the advertised web pages on the local network (the same list that
 186 Safari shows), use:
 187 .Pp
 188 .Dl Nm Fl B Ns \ _http._tcp
 189 .Pp
 190 While that command is running, in another window, try the
 191 .Nm Fl R
 192 example given above to advertise a web page, and you should see the
 193 "Add" event reported to the
 194 .Nm Fl B
 195 window. Now press Ctrl-C in the
 196 .Nm Fl R
 197 window and you should see the "Remove" event reported to the
 198 .Nm Fl B
 199 window.
 200 .Pp
 201 .Sh FILES
 202 .Pa /usr/bin/dns-sd \" Pathname
 203 .\"
 204 .Sh SEE ALSO
 205 .Xr mDNS 1
 206 .Xr mDNSResponder 8
 207 .\"
 208 .Sh BUGS
 209 .Nm
 210 bugs are tracked in Apple Radar component "mDNSResponder".
 211 .\"
 212 .Sh HISTORY
 213 The
 214 .Nm
 215 command first appeared in Mac OS X 10.4 (Tiger).