dns-sd(1)                    General Commands Manual                   dns-sd(1)

     dns-sd – Multicast DNS (mDNS) & DNS Service Discovery (DNS-SD) Test Tool

     dns-sd -E

     dns-sd -F

     dns-sd -R name type domain port [key=value ...]

     dns-sd -B type domain

     dns-sd -L name type domain

     dns-sd -P name type domain port host IP [key=value ...]

     dns-sd -q name rrtype rrclass

     dns-sd -Z type domain

     dns-sd -G v4/v6/v4v6 name

     dns-sd -V

     The dns-sd command is a network diagnostic tool, much like ping(8) or
     traceroute(8).  However, unlike those tools, most of its functionality is
     not implemented in the dns-sd executable itself, but in library code that
     is available to any application.  The library API that dns-sd uses is
     documented in /usr/include/dns_sd.h.  The dns-sd command replaces the older
     mDNS command.

     The dns-sd command is primarily intended for interactive use.  Because its
     command-line arguments and output format are subject to change, invoking it
     from a shell script will generally be fragile. Additionally, the
     asynchronous nature of DNS Service Discovery does not lend itself easily to
     script-oriented programming. For example, calls like "browse" never
     complete; the action of performing a "browse" sets in motion machinery to
     notify the client whenever instances of that service type appear or
     disappear from the network. These notifications continue to be delivered
     indefinitely, for minutes, hours, or even days, as services come and go,
     until the client explicitly terminates the call. This style of asynchronous
     interaction works best with applications that are either multi-threaded, or
     use a main event-handling loop to receive keystrokes, network data, and
     other asynchronous event notifications as they happen.
     If you wish to perform DNS Service Discovery operations from a scripting
     language, then the best way to do this is not to execute the dns-sd command
     and then attempt to decipher the textual output, but instead to directly
     call the DNS-SD APIs using a binding for your chosen language.
     For example, if you are programming in Ruby, then you can directly call
     DNS-SD APIs using the dnssd package documented at
     Similar bindings for other languages are also in development.

     dns-sd -E
        return a list of domains recommended for registering(advertising)

     dns-sd -F
        return a list of domains recommended for browsing services.

        Normally, on your home network, the only domain you are likely to see is
        "local".  However if your network administrator has created Domain
        Enumeration records, then you may also see other recommended domains for
        registering and browsing.

     dns-sd -R name type domain port [key=value ...]
        register (advertise) a service in the specified domain with the given
        name and type as listening (on the current machine) on port.

        name can be arbitrary unicode text, containing any legal unicode
        characters (including dots, spaces, slashes, colons, etc. without
        restriction), up to 63 UTF-8 bytes long.  type must be of the form
        "_app-proto._tcp" or "_app-proto._udp", where "app-proto" is an
        application protocol name registered at

        domain is the domain in which to register the service.  In current
        implementations, only the local multicast domain "local" is supported.
        In the future, registering will be supported in any arbitrary domain
        that has a working DNS Update server [RFC 2136]. The domain "." is a
        synonym for "pick a sensible default" which today means "local".

        port is a number from 0 to 65535, and is the TCP or UDP port number upon
        which the service is listening.

        Additional attributes of the service may optionally be described by
        key/value pairs, which are stored in the advertised service's DNS TXT
        record. Allowable keys and values are listed with the service
        registration at

     dns-sd -B type domain
        browse for instances of service type in domain.

        For valid types see
        as described above. Omitting the domain or using "." means "pick a
        sensible default."

     dns-sd -L name type domain
        look up and display the information necessary to contact and use the
        named service: the hostname of the machine where that service is
        available, the port number on which the service is listening, and (if
        present) TXT record attributes describing properties of the service.

        Note that in a typical application, browsing may only happen rarely,
        while lookup (or "resolving") happens every time the service is used.
        For example, a user browses the network to pick a default printer fairly
        rarely, but once a default printer has been picked, that named service
        is resolved to its current IP address and port number every time the
        user presses Cmd-P to print.

     dns-sd -P name type domain port host IP [key=value ...]
        create a proxy advertisement for a service running on(offered by) some
        other machine.  The two new options are Host, a name for the device and
        IP, the address of it.

        The service for which you create a proxy advertisement does not
        necessarily have to be on your local network.  You can set up a local
        proxy for a website on the Internet.

     dns-sd -q name rrtype rrclass
        look up any DNS name, resource record type, and resource record class,
        not necessarily DNS-SD names and record types.  If rrtype is not
        specified, it queries for the IPv4 address of the name, if rrclass is
        not specified, IN class is assumed. If the name is not a fully qualified
        domain name, then search domains may be appended.

     dns-sd -Z type domain
        browse for service instances and display output in zone file format.

     dns-sd -G v4/v6/v4v6 name
        look up the IP address information of the name.  If v4 is specified, the
        IPv4 address of the name is looked up, if v6 is specified the IPv6
        address is looked up. If v4v6 is specified both the IPv4 and IPv6
        address is looked up. If the name is not a fully qualified domain name,
        then search domains may be appended.

     dns-sd -V
        return the version of the currently running daemon/system service.

     To advertise the existence of LPR printing service on port 515 on this
     machine, such that it will be discovered by the Mac OS X printing software
     and other DNS-SD compatible printing clients, use:

           dns-sd -R "My Test" _printer._tcp. . 515 pdl=application/postscript

     For this registration to be useful, you need to actually have LPR service
     available on port 515. Advertising a service that does not exist is not
     very useful, and will be confusing and annoying to other people on the

     Similarly, to advertise a web page being served by an HTTP server on port
     80 on this machine, such that it will show up in the Bonjour list in Safari
     and other DNS-SD compatible Web clients, use:

           dns-sd -R "My Test" _http._tcp . 80 path=/path-to-page.html

     To find the advertised web pages on the local network (the same list that
     Safari shows), use:

           dns-sd -B _http._tcp

     While that command is running, in another window, try the dns-sd -R example
     given above to advertise a web page, and you should see the "Add" event
     reported to the dns-sd -B window. Now press Ctrl-C in the dns-sd -R window
     and you should see the "Remove" event reported to the dns-sd -B window.

     In the example below, the www.apple.com web page is advertised as a service
     called "apple", running on a target host called apple.local, which resolves

           dns-sd -P apple _http._tcp "" 80 apple.local

     The Bonjour menu in the Safari web browser will now show "apple".  The same
     IP address can be reached by entering apple.local in the web browser.  In
     either case, the request will be resolved to the IP address and browser
     will show contents associated with www.apple.com.

     If a client wants to be notified of changes in server state, it can
     initiate a query for the service's particular record and leave it running.
     For example, to monitor the status of an iChat user you can use:

           dns-sd -q someone@ex1._presence._tcp.local txt

     Everytime status of that user(someone) changes, you will see a new TXT
     record result reported.

     You can also query for a unicast name like www.apple.com and monitor its

           dns-sd -q www.apple.com



     dns-sd bugs are tracked in Apple Radar component "mDNSResponder".

     The dns-sd command first appeared in Mac OS X 10.4 (Tiger).

Darwin                             April 2004                             Darwin