mDNSShared/dns-sd.1

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  22 .\" $Log: dns-sd.1,v $
  23 .\" Revision 1.4  2005/02/16 02:29:32  cheshire
  24 .\" Update terminology
  25 .\"
  26 .\" Revision 1.3  2005/02/10 22:35:28  cheshire
  27 .\" <rdar://problem/3727944> Update name
  28 .\"
  29 .\" Revision 1.2  2004/09/24 18:33:05  cheshire
  30 .\" <rdar://problem/3561780> Update man pages to clarify that mDNS and dns-sd are not intended for script use
  31 .\"
  32 .\" Revision 1.1  2004/09/22 22:46:25  cheshire
  33 .\" Man page for dns-sd command-line tool
  34 .\"
  35 .\"
  36 .\"
  37 .Dd April 2004              \" Date
  38 .Dt dns-sd 1                \" Document Title
  39 .Os Darwin                  \" Operating System
  40 .\"
  41 .Sh NAME
  42 .Nm dns-sd
  43 .Nd Multicast DNS (mDNS) & DNS Service Discovery (DNS-SD) Test Tool \" For whatis
  44 .\"
  45 .Sh SYNOPSIS
  46 .Nm Fl R Ar name type domain port Op Ar key=value ...
  47 .Pp
  48 .Nm Fl B Ar      type domain
  49 .Pp
  50 .Nm Fl L Ar name type domain
  51 .\"
  52 .Sh DESCRIPTION
  53 The
  54 .Nm
  55 command is a network diagnostic tool, much like
  56 .Xr ping 8
  57 or
  58 .Xr traceroute 8 .
  59 However, unlike those tools, most of its functionality is not implemented in the
  60 .Nm
  61 executable itself, but in library code that is available to any application.
  62 The library API that
  63 .Nm
  64 uses is documented in
  65 .Pa /usr/include/dns_sd.h .
  66 The
  67 .Nm
  68 command replaces the older
  69 .Xr mDNS 1
  70 command.
  71 .Pp
  72 The
  73 .Nm
  74 command is primarily intended for interactive use.
  75 Because its command-line arguments and output format are subject to change,
  76 invoking it from a shell script will generally be fragile. Additionally,
  77 the asynchronous nature of DNS Service Discovery does
  78 not lend itself easily to script-oriented programming. For example,
  79 calls like "browse" never complete; the action of performing a "browse"
  80 sets in motion machinery to notify the client whenever instances of
  81 that service type appear or disappear from the network. These
  82 notifications continue to be delivered indefinitely, for minutes,
  83 hours, or even days, as services come and go, until the client
  84 explicitly terminates the call. This style of asynchronous interaction
  85 works best with applications that are either multi-threaded, or use a
  86 main event-handling loop to receive keystrokes, network data, and other
  87 asynchronous event notifications as they happen.
  88 .br
  89 If you wish to perform DNS Service Discovery operations from a
  90 scripting language, then the best way to do this is not to execute the
  91 .Nm
  92 command and then attempt to decipher the textual output, but instead to
  93 directly call the DNS-SD APIs using a binding for your chosen language.
  94 .br
  95 For example, if you are programming in Ruby, then you can
  96 directly call DNS-SD APIs using the dnssd package documented at
  97 .Pa <http://rubyforge.org/projects/dnssd/> .
  98 .br
  99 Similar bindings for other languages are also in development.
 100 .Pp
 101 .Bl -tag -width R
 102 .It Nm Fl R Ar name type domain port Op Ar key=value ...
 103 register (advertise) a service in the specified
 104 .Ar domain
 105 with the given
 106 .Ar name
 107 and
 108 .Ar type
 109 as listening (on the current machine) on
 110 .Ar port.
 111 .Pp
 112 .Ar name
 113 can be arbitrary unicode text, containing any legal unicode characters
 114 (including dots, spaces, slashes, colons, etc. without restriction),
 115 up to 63 UTF-8 bytes long.
 116 .Ar type
 117 must be of the form "_app-proto._tcp" or "_app-proto._udp", where
 118 "app-proto" is an application protocol name registered at
 119 .Pa http://www.dns-sd.org/ServiceTypes.html .
 120 .Pp
 121 .Ar domain
 122 is the domain in which to register the service.
 123 In current implementations, only the local multicast domain "local" is
 124 supported. In the future, registering will be supported in any arbitrary
 125 domain that has a working DNS Update server [RFC 2136]. The
 126 .Ar domain
 127 "." is a synonym for "pick a sensible default" which today
 128 means "local".
 129 .Pp
 130 .Ar port
 131 is a number from 0 to 65535, and is the TCP or UDP port number upon
 132 which the service is listening.
 133 .Pp
 134 Additional attributes of the service may optionally be described by
 135 key/value pairs, which are stored in the advertised service's DNS TXT
 136 record. Allowable keys and values are listed with the service
 137 registration at
 138 .Pa http://www.dns-sd.org/ServiceTypes.html .
 139 .It Nm Fl B Ar type domain
 140 browse for instances of service
 141 .Ar type
 142 in
 143 .Ar domain .
 144 .Pp
 145 For valid
 146 .Ar type Ns s
 147 see
 148 .Pa http://www.dns-sd.org/ServiceTypes.html
 149 as described above. Omitting the
 150 .Ar domain
 151 or using "." means "pick a sensible default."
 152 .It Nm Fl L Ar name type domain
 153 look up and display the information necessary to contact and use the
 154 named service: the hostname of the machine where that service is
 155 available, the port number on which the service is listening, and (if
 156 present) TXT record attributes describing properties of the service.
 157 .Pp
 158 Note that in a typical application, browsing happens rarely, while lookup
 159 (or "resolving") happens every time the service is used. For example, a
 160 user browses the network to pick a default printer fairly rarely, but once
 161 a default printer has been picked, that named service is resolved to its
 162 current IP address and port number every time the user presses Cmd-P to
 163 print.
 164 .El
 165 .Sh EXAMPLES
 166 .Pp
 167 To advertise the existence of LPR printing service on port 515 on this
 168 machine, such that it will be discovered by the Mac OS X printing software
 169 and other DNS-SD compatible printing clients, use:
 170 .Pp
 171 .Dl Nm Fl R Ns \ \&"My Test\&" _printer._tcp. \&. 515 pdl=application/postscript
 172 .Pp
 173 For this registration to be useful, you need to actually have LPR service
 174 available on port 515. Advertising a service that does not exist is not
 175 very useful, and will be confusing and annoying to other people on the
 176 network.
 177 .Pp
 178 Similarly, to advertise a web page being served by an HTTP
 179 server on port 80 on this machine, such that it will show up in the
 180 Bonjour list in Safari and other DNS-SD compatible Web clients, use:
 181 .Pp
 182 .Dl Nm Fl R Ns \ \&"My Test\&" _http._tcp \&. 80 path=/path-to-page.html
 183 .Pp
 184 To find the advertised web pages on the local network (the same list that
 185 Safari shows), use:
 186 .Pp
 187 .Dl Nm Fl B Ns \ _http._tcp
 188 .Pp
 189 While that command is running, in another window, try the
 190 .Nm Fl R
 191 example given above to advertise a web page, and you should see the
 192 "Add" event reported to the
 193 .Nm Fl B
 194 window. Now press Ctrl-C in the
 195 .Nm Fl R
 196 window and you should see the "Remove" event reported to the
 197 .Nm Fl B
 198 window.
 199 .Pp
 200 .Sh FILES
 201 .Pa /usr/bin/dns-sd \" Pathname
 202 .\"
 203 .Sh SEE ALSO
 204 .Xr mDNS 1
 205 .Xr mDNSResponder 8
 206 .\"
 207 .Sh BUGS
 208 .Nm
 209 bugs are tracked in Apple Radar component "mDNSResponder".
 210 .\"
 211 .Sh HISTORY
 212 The
 213 .Nm
 214 command first appeared in Mac OS X 10.3 (Panther).