mDNSShared/dns-sd.1

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  17 .Dd April 2004              \" Date
  18 .Dt dns-sd 1                \" Document Title
  19 .Os Darwin                  \" Operating System
  20 .\"
  21 .Sh NAME
  22 .Nm dns-sd
  23 .Nd Multicast DNS (mDNS) & DNS Service Discovery (DNS-SD) Test Tool \" For whatis
  24 .\"
  25 .Sh SYNOPSIS
  26 .Nm Fl E
  27 .Pp
  28 .Nm Fl F
  29 .Pp
  30 .Nm Fl R Ar name type domain port Op Ar key=value ...
  31 .Pp
  32 .Nm Fl B Ar      type domain
  33 .Pp
  34 .Nm Fl L Ar name type domain
  35 .Pp
  36 .Nm Fl P Ar name type domain port host IP Op Ar key=value ...
  37 .Pp
  38 .Nm Fl q Ar name rrtype rrclass
  39 .Pp
  40 .Nm Fl Z Ar      type domain
  41 .Pp
  42 .Nm Fl G Ns \ v4/v6/v4v6 Ar      name
  43 .Pp
  44 .Nm Fl V
  45 .\"
  46 .Sh DESCRIPTION
  47 The
  48 .Nm
  49 command is a network diagnostic tool, much like
  50 .Xr ping 8
  51 or
  52 .Xr traceroute 8 .
  53 However, unlike those tools, most of its functionality is not implemented in the
  54 .Nm
  55 executable itself, but in library code that is available to any application.
  56 The library API that
  57 .Nm
  58 uses is documented in
  59 .Pa /usr/include/dns_sd.h .
  60 The
  61 .Nm
  62 command replaces the older
  63 mDNS
  64 command.
  65 .Pp
  66 The
  67 .Nm
  68 command is primarily intended for interactive use.
  69 Because its command-line arguments and output format are subject to change,
  70 invoking it from a shell script will generally be fragile. Additionally,
  71 the asynchronous nature of DNS Service Discovery does
  72 not lend itself easily to script-oriented programming. For example,
  73 calls like "browse" never complete; the action of performing a "browse"
  74 sets in motion machinery to notify the client whenever instances of
  75 that service type appear or disappear from the network. These
  76 notifications continue to be delivered indefinitely, for minutes,
  77 hours, or even days, as services come and go, until the client
  78 explicitly terminates the call. This style of asynchronous interaction
  79 works best with applications that are either multi-threaded, or use a
  80 main event-handling loop to receive keystrokes, network data, and other
  81 asynchronous event notifications as they happen.
  82 .br
  83 If you wish to perform DNS Service Discovery operations from a
  84 scripting language, then the best way to do this is not to execute the
  85 .Nm
  86 command and then attempt to decipher the textual output, but instead to
  87 directly call the DNS-SD APIs using a binding for your chosen language.
  88 .br
  89 For example, if you are programming in Ruby, then you can
  90 directly call DNS-SD APIs using the dnssd package documented at
  91 .Pa <http://rubyforge.org/projects/dnssd/> .
  92 .br
  93 Similar bindings for other languages are also in development.
  94 .Pp
  95 .Bl -tag -width E
  96 .It Nm Fl E
  97 return a list of domains recommended for registering(advertising) services.
  98 .Pp
  99 .It Nm Fl F
 100 return a list of domains recommended for browsing services.
 101 .Pp
 102 Normally, on your home network, the only domain you are likely to see is "local".
 103 However if your network administrator has created Domain Enumeration records,
 104 then you may also see other recommended domains for registering and browsing.
 105 .Pp
 106 .It Nm Fl R Ar name type domain port Op Ar key=value ...
 107 register (advertise) a service in the specified
 108 .Ar domain
 109 with the given
 110 .Ar name
 111 and
 112 .Ar type
 113 as listening (on the current machine) on
 114 .Ar port.
 115 .Pp
 116 .Ar name
 117 can be arbitrary unicode text, containing any legal unicode characters
 118 (including dots, spaces, slashes, colons, etc. without restriction),
 119 up to 63 UTF-8 bytes long.
 120 .Ar type
 121 must be of the form "_app-proto._tcp" or "_app-proto._udp", where
 122 "app-proto" is an application protocol name registered at
 123 .Pa http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml .
 124 .Pp
 125 .Ar domain
 126 is the domain in which to register the service.
 127 In current implementations, only the local multicast domain "local" is
 128 supported. In the future, registering will be supported in any arbitrary
 129 domain that has a working DNS Update server [RFC 2136]. The
 130 .Ar domain
 131 "." is a synonym for "pick a sensible default" which today
 132 means "local".
 133 .Pp
 134 .Ar port
 135 is a number from 0 to 65535, and is the TCP or UDP port number upon
 136 which the service is listening.
 137 .Pp
 138 Additional attributes of the service may optionally be described by
 139 key/value pairs, which are stored in the advertised service's DNS TXT
 140 record. Allowable keys and values are listed with the service
 141 registration at
 142 .Pa http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml .
 143 .It Nm Fl B Ar type domain
 144 browse for instances of service
 145 .Ar type
 146 in
 147 .Ar domain .
 148 .Pp
 149 For valid
 150 .Ar type Ns s
 151 see
 152 .Pa http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xml .
 153 as described above. Omitting the
 154 .Ar domain
 155 or using "." means "pick a sensible default."
 156 .It Nm Fl L Ar name type domain
 157 look up and display the information necessary to contact and use the
 158 named service: the hostname of the machine where that service is
 159 available, the port number on which the service is listening, and (if
 160 present) TXT record attributes describing properties of the service.
 161 .Pp
 162 Note that in a typical application, browsing may only happen rarely, while lookup
 163 (or "resolving") happens every time the service is used. For example, a
 164 user browses the network to pick a default printer fairly rarely, but once
 165 a default printer has been picked, that named service is resolved to its
 166 current IP address and port number every time the user presses Cmd-P to
 167 print.
 168 .Pp
 169 .It Nm Fl P Ar name type domain port host IP Op Ar key=value ...
 170 create a proxy advertisement for a service running on(offered by) some other machine.
 171 The two new options are Host, a name for the device and IP, the address of it.
 172 .Pp
 173 The service for which you create a proxy advertisement does not necessarily have to be on your local network.
 174 You can set up a local proxy for a website on the Internet.
 175 .Pp
 176 .It Nm Fl q Ar name rrtype rrclass
 177 look up any DNS name, resource record type, and resource record class,
 178 not necessarily DNS-SD names and record types.
 179 If rrtype is not specified, it queries for the IPv4 address of the name,
 180 if rrclass is not specified, IN class is assumed. If the name is not a fully
 181 qualified domain name, then search domains may be appended.
 182 .Pp
 183 .It Nm Fl Z Ar type domain
 184 browse for service instances and display output in zone file format.
 185 .Pp
 186 .It Nm Fl G Ns \ v4/v6/v4v6 Ar name
 187 look up the IP address information of the name.
 188 If v4 is specified, the IPv4 address of the name is looked up,
 189 if v6 is specified the IPv6 address is looked up. If v4v6 is specified both the IPv4 and IPv6
 190 address is looked up. If the name is not a fully qualified domain name,
 191 then search domains may be appended.
 192 .Pp
 193 .It Nm Fl V
 194 return the version of the currently running daemon/system service.
 195 .El
 196 .Sh EXAMPLES
 197 .Pp
 198 To advertise the existence of LPR printing service on port 515 on this
 199 machine, such that it will be discovered by the Mac OS X printing software
 200 and other DNS-SD compatible printing clients, use:
 201 .Pp
 202 .Dl Nm Fl R Ns \ \&"My Test\&" _printer._tcp. \&. 515 pdl=application/postscript
 203 .Pp
 204 For this registration to be useful, you need to actually have LPR service
 205 available on port 515. Advertising a service that does not exist is not
 206 very useful, and will be confusing and annoying to other people on the
 207 network.
 208 .Pp
 209 Similarly, to advertise a web page being served by an HTTP
 210 server on port 80 on this machine, such that it will show up in the
 211 Bonjour list in Safari and other DNS-SD compatible Web clients, use:
 212 .Pp
 213 .Dl Nm Fl R Ns \ \&"My Test\&" _http._tcp \&. 80 path=/path-to-page.html
 214 .Pp
 215 To find the advertised web pages on the local network (the same list that
 216 Safari shows), use:
 217 .Pp
 218 .Dl Nm Fl B Ns \ _http._tcp
 219 .Pp
 220 While that command is running, in another window, try the
 221 .Nm Fl R
 222 example given above to advertise a web page, and you should see the
 223 "Add" event reported to the
 224 .Nm Fl B
 225 window. Now press Ctrl-C in the
 226 .Nm Fl R
 227 window and you should see the "Remove" event reported to the
 228 .Nm Fl B
 229 window.
 230 .Pp
 231 In the example below, the www.apple.com web page is advertised as a service called "apple",
 232 running on a target host called apple.local, which resolves to 17.149.160.49.
 233 .Pp
 234 .Dl Nm Fl P Ns \ apple _http._tcp \&"\&"\& 80 apple.local 17.149.160.49
 235 .Pp
 236 The Bonjour menu in the Safari web browser will now show "apple".
 237 The same IP address can be reached by entering apple.local in the web browser.
 238 In either case, the request will be resolved to the IP address and browser will show
 239 contents associated with www.apple.com.
 240 .Pp
 241 If a client wants to be notified of changes in server state, it can
 242 initiate a query for the service's particular record and leave it running.
 243 For example, to monitor the status of an iChat user you can use:
 244 .Pp
 245 .Dl Nm Fl q Ns \ someone@ex1._presence._tcp.local txt
 246 .Pp
 247 Everytime status of that user(someone) changes, you will see a new TXT record result reported.
 248 .Pp
 249 You can also query for a unicast name like www.apple.com and monitor its status.
 250 .Pp
 251 .Dl Nm Fl q Ns \ www.apple.com
 252 .Pp
 253 .Sh FILES
 254 .Pa /usr/bin/dns-sd \" Pathname
 255 .\"
 256 .Sh SEE ALSO
 257 .Xr mDNSResponder 8
 258 .\"
 259 .Sh BUGS
 260 .Nm
 261 bugs are tracked in Apple Radar component "mDNSResponder".
 262 .\"
 263 .Sh HISTORY
 264 The
 265 .Nm
 266 command first appeared in Mac OS X 10.4 (Tiger).