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dns-sd(1)		FreeBSD	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, in-
     voking 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	ma-
     chinery to	notify the client whenever instances of	that service type ap-
     pear 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 com-
     mand and then attempt to decipher the textual output, but instead to di-
     rectly 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) ser-

     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 char-
	acters (including dots,	spaces,	slashes, colons, etc. without restric-
	tion), 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 im-
	plementations, 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 regis-
	tration	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	neces-
	sarily 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 spec-
	ified, 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 ad-
	dress 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 soft-
     ware 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 Sa-
     fari 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 exam-
     ple 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

     In	the example below, the web page is advertised as a ser-
     vice called "apple", running on a target host called apple.local, which
     resolves to

	   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

     If	a client wants to be notified of changes in server state, it can ini-
     tiate 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 and monitor its

	   dns-sd -q



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

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

Darwin			       December	5, 2021				Darwin


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