draft-ietf-urn-naptr-rr-01.txt		draft-ietf-urn-naptr-rr-02.txt
	Network Working Group M. Mealling		Network Working Group M. Mealling
	draft-ietf-urn-naptr-rr-01.txt Network Solutions, Inc.		draft-ietf-urn-naptr-rr-02.txt Network Solutions, Inc.
	Category: Standards Track R. Daniel		Category: Standards Track R. Daniel
	Expires: August, 1999 DATAFUSION, Inc.		Expires: September, 1999 DATAFUSION, Inc.
	The Naming Authority Pointer (NAPTR) DNS Resource Record		The Naming Authority Pointer (NAPTR) DNS Resource Record
	Status of this Memo		Status of this Memo
	===================		===================
	This document is an Internet-Draft and is in full conformance		This document is an Internet-Draft and is in full conformance
	with all provisions of Section 10 of RFC2026.		with all provisions of Section 10 of RFC2026.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	skipping to change at page 10, line ?		skipping to change at page 10, line ?
	domain. While all hosts, such as mordred, could have their very own		domain. While all hosts, such as mordred, could have their very own
	NAPTR, maintaining those records for all the machines at a site as		NAPTR, maintaining those records for all the machines at a site as
	large as Georgia Tech would be an intolerable burden. Wildcards are		large as Georgia Tech would be an intolerable burden. Wildcards are
	not appropriate here since they only return results when there is no		not appropriate here since they only return results when there is no
	exactly matching names already in the system.		exactly matching names already in the system.
	The record returned from the query on "gatech.edu" might look like:		The record returned from the query on "gatech.edu" might look like:
	gatech.edu IN NAPTR		gatech.edu IN NAPTR
	;; order pref flags service regexp replacement		;; order pref flags service regexp replacement
	IN NAPTR 100 50 "s" "z3950+N2L+N2C" "" z3950.tcp.gatech.edu		IN NAPTR 100 50 "s" "z3950+N2L+N2C" "" _z3950._tcp.gatech.edu
	IN NAPTR 100 50 "s" "rcds+N2C" "" rcds.udp.gatech.edu		IN NAPTR 100 50 "s" "rcds+N2C" "" _rcds._udp.gatech.edu
	IN NAPTR 100 50 "s" "http+N2L+N2C+N2R" "" http.tcp.gatech.edu		IN NAPTR 100 50 "s" "http+N2L+N2C+N2R" "" _http._tcp.gatech.edu
	Continuing with the example, note that the values of the order and		Continuing with the example, note that the values of the order and
	preference fields are equal in all records, so the client is free to		preference fields are equal in all records, so the client is free to
	pick any record. The flags field tells us that these are the last		pick any record. The flags field tells us that these are the last
	NAPTR patterns we should see, and after the rewrite (a simple		NAPTR patterns we should see, and after the rewrite (a simple
	replacement in this case) we should look up SRV records to get		replacement in this case) we should look up SRV records to get
	information on the hosts that can provide the necessary service.		information on the hosts that can provide the necessary service.
	Assuming we prefer the Z39.50 protocol, our lookup might return:		Assuming we prefer the Z39.50 protocol, our lookup might return:
	;; Pref Weight Port Target		;; Pref Weight Port Target
	z3950.tcp.gatech.edu IN SRV 0 0 1000 z3950.gatech.edu		_z3950._tcp.gatech.edu IN SRV 0 0 1000 z3950.gatech.edu
	IN SRV 0 0 1000 z3950.cc.gatech.edu		IN SRV 0 0 1000 z3950.cc.gatech.edu
	IN SRV 0 0 1000 z3950.uga.edu		IN SRV 0 0 1000 z3950.uga.edu
	telling us three hosts that could actually do the resolution, and		telling us three hosts that could actually do the resolution, and
	giving us the port we should use to talk to their Z39.50 server.		giving us the port we should use to talk to their Z39.50 server.
	Recall that the regular expression used \2 to extract a domain name		Recall that the regular expression used \2 to extract a domain name
	from the CID, and \. for matching the literal '.' characters		from the CID, and \. for matching the literal '.' characters
	separating the domain name components. Since '\' is the escape		separating the domain name components. Since '\' is the escape
	character, literal occurances of a backslash must be escaped by		character, literal occurances of a backslash must be escaped by
	skipping to change at page 10, line ?		skipping to change at page 10, line ?
	the parts of the substitution expression. Otherwise we would have to		the parts of the substitution expression. Otherwise we would have to
	use backslashes to escape the forward slashes and would have a		use backslashes to escape the forward slashes and would have a
	regexp in the zone file that looked like		regexp in the zone file that looked like
	"/http:\\/\\/([^\\/:]+)/\\1/i".).		"/http:\\/\\/([^\\/:]+)/\\1/i".).
	Applying this pattern to the URL extracts "www.foo.com". Looking up		Applying this pattern to the URL extracts "www.foo.com". Looking up
	NAPTR records for that might return:		NAPTR records for that might return:
	www.foo.com		www.foo.com
	;; order pref flags service regexp replacement		;; order pref flags service regexp replacement
	IN NAPTR 100 100 "s" "http+L2R" "" http.tcp.foo.com		IN NAPTR 100 100 "s" "http+L2R" "" _http._tcp.foo.com
	IN NAPTR 100 100 "s" "ftp+L2R" "" ftp.tcp.foo.com		IN NAPTR 100 100 "s" "ftp+L2R" "" _ftp._tcp.foo.com
	Looking up SRV records for http.tcp.foo.com would return information		Looking up SRV records for http.tcp.foo.com would return information
	on the hosts that foo.com has designated to be its mirror sites. The		on the hosts that foo.com has designated to be its mirror sites. The
	client can then pick one for the user.		client can then pick one for the user.
	Example 3		Example 3
	---------		---------
	A non-URI example is where a NAPTR is used to specify the available		A non-URI example is where a NAPTR is used to specify the available
	mappings from a domain-name to telephony based endpoints. In this		mappings from a domain-name to telephony based endpoints. In this
	example the regular expression field is not used since the important		example the regular expression field is not used since the important
	information is encoded within the services field.		information is encoded within the services field.
	0.0.0.4.6.2.6.5.8.6.4.e164.int.		0.0.0.4.6.2.6.5.8.6.4.e164.int.
	IN NAPTR 100 10 "s" "h323call+N2R" "" tele2.se.		IN NAPTR 100 10 "s" "h323call+N2R" "" _h323._udp.tele2.se.
	IN NAPTR 102 10 "s" "potscall+N2R" "" tele2.se.		IN NAPTR 102 10 "s" "potscall+N2R" "" _potscall._tcp.tele2.se.
	IN NAPTR 102 10 "s" "smtp+N2R" "" tele2.se.		IN NAPTR 102 10 "s" "smtp+N2R" "" _smtp._tcp.tele2.se.
	In these examples the domain is an encoded E164 telephone number.		In these examples the domain is an encoded E164 telephone number.
	The services field specifies that, for this particular telephone		The services field specifies that, for this particular telephone
	number, the services that are available are h323call, potscall		number, the services that are available are h323call, potscall
	and smtp; and that "tele2.se" is the target that provides those		and smtp; and that "tele2.se" is the target that provides those
	services. Since the flag is "s", the next step should be a		services. Since the flag is "s", the next step should be a
	query for an SRV record which will contain specific information		query for an SRV record which will contain specific information
	about the "tele2.se" domain.		about the "tele2.se" domain.
	DNS Packet Format		DNS Packet Format
End of changes. 6 change blocks.
	11 lines changed or deleted		11 lines changed or added
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