< draft-eastlake-dnsext-cookies-00.txt		draft-eastlake-dnsext-cookies-01.txt >
	INTERNET-DRAFT Donald E. Eastlake 3rd		INTERNET-DRAFT Donald E. Eastlake 3rd
	Motorola Laboratories		Motorola Laboratories
	Expires: December 2006 June 2006		Expires: April 2007 October 2006
	Domain Name System (DNS) Cookies		Domain Name System (DNS) Cookies
	------ ---- ------ ----- -------		------ ---- ------ ----- -------
	<draft-eastlake-dnsext-cookies-00.txt>		<draft-eastlake-dnsext-cookies-01.txt>
	Status of This Document		Status of This Document
	By submitting this Internet-Draft, each author represents that any		By submitting this Internet-Draft, each author represents that any
	applicable patent or other IPR claims of which he or she is aware		applicable patent or other IPR claims of which he or she is aware
	have been or will be disclosed, and any of which he or she becomes		have been or will be disclosed, and any of which he or she becomes
	aware will be disclosed, in accordance with Section 6 of BCP 79.		aware will be disclosed, in accordance with Section 6 of BCP 79.
	This draft is intended to be become a Proposed Standard RFC.		This draft is intended to be become a Proposed Standard RFC.
	Distribution of this document is unlimited. Comments should be sent		Distribution of this document is unlimited. Comments should be sent
	skipping to change at page 2, line 24 ¶		skipping to change at page 2, line 24 ¶
	1. Introduction............................................3		1. Introduction............................................3
	1.1 Contents of This Document..............................3		1.1 Contents of This Document..............................3
	1.2 Definitions............................................3		1.2 Definitions............................................3
	2. Threats Considered......................................4		2. Threats Considered......................................4
	2.1 Denial-of-Service Attacks..............................4		2.1 Denial-of-Service Attacks..............................4
	2.1.1 DNS Server Denial-of-Service.........................4		2.1.1 DNS Server Denial-of-Service.........................4
	2.1.2 Selected Host Denial-of-Service......................5		2.1.2 Selected Host Denial-of-Service......................5
	2.2 Cache Poisoning Attacks................................5		2.2 Cache Poisoning Attacks................................5
	3. Comments on Existing DNS Security.......................5		3. Comments on Existing DNS Security.......................5
	4. The COOKIE RR...........................................6		4. The COOKIE OPT option...................................6
	4.1 Resolver Cookies.......................................7		4.1 Resolver Cookies.......................................7
	4.2 Server Cookies.........................................7		4.2 Server Cookies.........................................8
	5. General Policies and Implementation.....................8		5. General Policies and Implementation.....................8
	5.1 Resolver Policies and Implementation...................8		5.1 Resolver Policies and Implementation...................9
	5.2 Server Policies and Implementation.....................9		5.2 Server Policies and Implementation.....................9
	5.3 Implementation Requirements...........................10		5.3 Implementation Requirements...........................10
	6. NAT and AnyCast Considerations.........................10		6. NAT and AnyCast Considerations.........................10
	7. IANA Considerations....................................12		7. IANA Considerations....................................12
	8. Security Considerations................................12		8. Security Considerations................................12
	9. Copyright and Disclaimer...............................13		9. Copyright and Disclaimer...............................13
	10. Normative References..................................13		10. Normative References..................................13
	11. Informative References................................13		11. Informative References................................14
	Author's Address..........................................15		Author's Address..........................................15
	Additional IPR Provisions.................................15		Additional IPR Provisions.................................15
	Expiration and File Name..................................15		Expiration and File Name..................................15
	INTERNET-DRAFT DNS Cookies		INTERNET-DRAFT DNS Cookies
	1. Introduction		1. Introduction
	The Domain Name System (DNS) provides a replicated distributed		The Domain Name System (DNS) provides a replicated distributed
	database which stores "resource records" (RRs) under hierarchical		database which stores "resource records" (RRs) under hierarchical
	domain names. DNS data is structured into CLASSes and zones which		domain names. DNS data is structured into CLASSes and zones which
	can be independently maintained. See [STD 13], [RFC 2181]		can be independently maintained. See [STD13], [RFC2181] familiarity
	familiarity with which is assumed.		with which is assumed.
	As with many core Internet protocols, DNS was designed at a time when		As with many core Internet protocols, DNS was designed at a time when
	the Internet had only a small pool of trusted users. As the Internet		the Internet had only a small pool of trusted users. As the Internet
	has exploded to a global information utility the DNS has increasingly		has exploded to a global information utility the DNS has increasingly
	been subject to abuse and been used as a vector for abuse.		been subject to abuse and been used as a vector for abuse.
	This document describes DNS cookies, a light-weight DNS transaction		This document describes DNS cookies, a light-weight DNS transaction
	security mechanism. They provides limited protection to DNS servers		security mechanism specified as an OPT [RFC2671] option. They
	and resolvers against a variety of increasingly common denial-of-		provides limited protection to DNS servers and resolvers against a
	service and cache poisoning attacks by off-path attackers.		variety of increasingly common denial-of-service and cache poisoning
			attacks by off-path attackers.
	1.1 Contents of This Document		1.1 Contents of This Document
	In Section 2, we discuss the threats against which DNS cookies		In Section 2, we discuss the threats against which DNS cookies
	provides some protection.		provides some protection.
	Section 3 describes existing DNS security mechanisms and why they are		Section 3 describes existing DNS security mechanisms and why they are
	not adequate subsitutes for DNS cookies.		not adequate substitutes for DNS cookies.
	Section 4 describes the COOKIE RR including how recommendations for		Section 4 describes the COOKIE OPT option including recommendations
	calculating Resolver and Server Cookies.		for calculating Resolver and Server Cookies.
	Section 5 describes the processing of COOKIE RRs by resolvers and		Section 5 describes the processing of COOKIE OPT optionby resolvers
	server and policies for such processing.		and server and policies for such processing.
	Section 6 discusses some NAT and anycast related DNS Cookies design		Section 6 discusses some NAT and anycast related DNS Cookies design
	considerations.		considerations.
	Sections 7 and 8 describe IANA and Security Considerations.		Sections 7 and 8 describe IANA and Security Considerations.
	1.2 Definitions		1.2 Definitions
	The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",		The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
	"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this		"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
	document are to be interpreted as described in RFC 2119.		document are to be interpreted as described in [RFC2119].
	An "off-path attacker", for a particular DNS resolver and server, is		An "off-path attacker", for a particular DNS resolver and server, is
	defined as an attacker which cannot observe the legitimate plain text		defined as an attacker which cannot observe the legitimate plain text
	DNS requests and responses between that resolver and server.
	INTERNET-DRAFT DNS Cookies		INTERNET-DRAFT DNS Cookies
			DNS requests and responses between that resolver and server.
	"Soft state" indicates information learned or derived by a host which		"Soft state" indicates information learned or derived by a host which
	may be discarded when indicated by the policies of that host. For		may be discarded when indicated by the policies of that host. For
	example, it could be discarded after a period of time or when storage		example, it could be discarded after a period of time or when storage
	for caching such data becomes full. If operations requiring that soft		for caching such data becomes full. If operations requiring that soft
	state continue after it has been discarded, it will be automatically		state continue after it has been discarded, it will be automatically
	re-generated, albeit at some cost.		re-generated, albeit at some cost.
	"Silently discarded" indicates that there are no DNS protocol message		"Silently discarded" indicates that there are no DNS protocol message
	consequences; however, it is RECOMMENDED that appropriate debugging		consequences; however, it is RECOMMENDED that appropriate debugging
	network management facilities be included in implementations, such as		network management facilities be included in implementations, such as
	skipping to change at page 4, line 31 ¶		skipping to change at page 4, line 33 ¶
	2. Threats Considered		2. Threats Considered
	DNS cookies are intended to provide significant but limited		DNS cookies are intended to provide significant but limited
	protection against certain denial-of-service and cache poisoning		protection against certain denial-of-service and cache poisoning
	attacks by off-path attackers described below.		attacks by off-path attackers described below.
	2.1 Denial-of-Service Attacks		2.1 Denial-of-Service Attacks
	The normal form of the denial-of-service attacks considered herein is		The normal form of the denial-of-service attacks considered herein is
	to send DNS requests to the attacked server with forged source IP		to send DNS requests with forged source IP addresses to a server. The
	addresses. The intent can be to attack the server or a selected host		intent can be to attack that server or a selected host as described
	as described below.		below.
	2.1.1 DNS Server Denial-of-Service		2.1.1 DNS Server Denial-of-Service
	DNS requests that are accepted cause work on the part of DNS servers.		DNS requests that are accepted cause work on the part of DNS servers.
	This is particularly true for recursive servers which may issue one		This is particularly true for recursive servers which may issue one
	or more requests and process the responses thereto in order to		or more requests and process the responses thereto in order to
	determine their response to the initial query. And the situation is		determine their response to the initial query. And the situation is
	even worse for recursive servers implementing DNSSEC [RFC 4033], [RFC		even worse for recursive servers implementing DNSSEC [RFC4033],
	4034], [RFC 4035] because they may be induced to perform burdensome		[RFC4034], [RFC4035] because they may be induced to perform
	public key cryptographic computations in attempts to verify the		burdensome public key cryptographic computations in attempts to
	authenticity of data they retrieve in trying to answer the request.		verify the authenticity of data they retrieve in trying to answer the
			request.
	While the burden cause by such requests is not dependent on a forged		While the burden cause by such requests is not dependent on a forged
	IP source address, the use of such addresses makes		IP source address, the use of such addresses makes
	+ the source of the requests causing the denial-of-service requests
	to be harder to find and
	+ administrative restriction of the IP addresses from which such
	INTERNET-DRAFT DNS Cookies		INTERNET-DRAFT DNS Cookies
			+ the source of the requests causing the denial-of-service requests
			to be harder to find and
			+ administrative restriction of the IP addresses from which such
	requests should be honored harder to enforce.		requests should be honored harder to enforce.
	2.1.2 Selected Host Denial-of-Service		2.1.2 Selected Host Denial-of-Service
	Request with a forged IP address causes a response to be sent to that		Request with a forged IP address causes a response to be sent to that
	forged IP address. Thus the forging of many such requests can,		forged IP address. Thus the forging of many such requests can,
	indirectly, result in enough traffic being sent to the forged IP		indirectly, result in enough traffic being sent to the forged IP
	address to interfere with service to the host at the IP address.		address to interfere with service to the host at the IP address.
	Furthermore, it is generally easy in the DNS to create short requests		Furthermore, it is generally easy in the DNS to create short requests
	that produce much longer responses. Thus a DNS server can be used as		that produce much longer responses. Thus a DNS server can be used as
	not only a way to obscure the true source of an attack but as a		not only a way to obscure the true source of an attack but as a
	traffic amplifier to make the attack more effective.		traffic amplifier to make the attack more effective.
	Use of DNS cookies severely limits the traffic amplification that can		Use of DNS cookies severely limits the traffic amplification that can
	be obtained by attackers off path for the server and the attacked		be obtained by attackers off path for the server and the attacked
	host. Enforced DNS cookies would make it hard for an off path		host. Enforced DNS cookies would make it hard for an off path
	attacker to cause any more than a brief error response to be send to		attacker to cause any more than a brief error response to be send to
	a forged IP address. Furthermore, DNS cookies make it more effective		a forged IP address. Furthermore, DNS cookies make it more effective
	to implement a rate limiting scheme for bad DNS cookie error response		to implement a rate limiting scheme for bad DNS cookie error response
	from the server which would further restrict selected host denial-of-		from the server. Such a scheme would further restrict selected host
	service traffic from that server.		denial-of-service traffic from that server.
	2.2 Cache Poisoning Attacks		2.2 Cache Poisoning Attacks
	The form of the cache poisoning attacks considered is to send forged		The form of the cache poisoning attacks considered is to send forged
	replies to a resolver. Modern network speeds for well connected hosts		replies to a resolver. Modern network speeds for well connected hosts
	are such that, by forging replies from the IP addresses of heavily		are such that, by forging replies from the IP addresses of heavily
	used DNS servers and for popular names to a heavily used resolver,		used DNS servers and for popular names to a heavily used resolver,
	there can be an unacceptably high probability of randomly coming up		there can be an unacceptably high probability of randomly coming up
	with a reply that will be accepted and cause false DNS information to		with a reply that will be accepted and cause false DNS information to
	be cached by that resolver. This can be used to facilitate phishing		be cached by that resolver. This can be used to facilitate phishing
	attacks and other diversion of legitimate traffic to a compromised or		attacks and other diversion of legitimate traffic to a compromised or
	malicious host such as a web server.		malicious host such as a web server.
	3. Comments on Existing DNS Security		3. Comments on Existing DNS Security
	Two forms of security have been added to DNS:		Two forms of security have been added to DNS:
	The first, called DNSSEC and described in [RFC 4033], [RFC 4034],		The first, called DNSSEC and described in [RFC4033], [RFC4034], and
	[RFC 4035], provides data origin authentication and authenticated		[RFC4035], provides data origin authentication and authenticated
	denial of existence. It is being deployed very slowly and, in any		denial of existence. It is being deployed very slowly and, in any
			INTERNET-DRAFT DNS Cookies
	case, can make some denial-of-service attacks worse because of the		case, can make some denial-of-service attacks worse because of the
	high cryptographic computational load it can require and the		high cryptographic computational load it can require and the
	increased size in DNS packets that it can produces.		increased size in DNS packets that it can produces.
	INTERNET-DRAFT DNS Cookies
	The second form of security which has been added to DNS provides		The second form of security which has been added to DNS provides
	"transaction" security through TSIG [RFC 2845] or SIG(0) [RFC 2931].		"transaction" security through TSIG [RFC2845] or SIG(0) [RFC2931].
	TSIG could provide near perfect protection against the attacks for		TSIG could provide near perfect protection against the attacks for
	which DNS cookies provide weak and incomplete protection; however,		which DNS cookies provide weak and incomplete protection; however,
	TSIG is hard to deploy in the general Internet because of the burden		TSIG is hard to deploy in the general Internet because of the burden
	it imposes of pre-agreement and key distribution between pairs of		it imposes of pre-agreement and key distribution between pairs of
	resolvers and servers and because it requires time synchronization		resolvers and servers and because it requires time synchronization
	between resolver and server.		between resolver and server.
	TKEY [RFC 2930] can solve the problem of key distribution for TSIG		TKEY [RFC2930] can solve the problem of key distribution for TSIG but
	but some modes of TKEY impose substantial cryptographic computations		some modes of TKEY impose substantial cryptographic computations
	loads and can be dependent on the deployment of DNSSEC.		loads and can be dependent on the deployment of DNSSEC.
	SIG(0) provides less protection than TSIG or, in one way, even DNS		SIG(0) provides less protection than TSIG or, in one way, even DNS
	cookies, because it does not authentication requests, only complete		cookies, because it does not authentication requests, only complete
	transactions. In any case, it also depends on the deployment of		transactions. In any case, it also depends on the deployment of
	DNSSEC and requires computationally burdensome public key		DNSSEC and requires computationally burdensome public key
	cryptographic operations.		cryptographic operations.
	Thus, none of the previous forms of DNS security are a suitable		Thus, none of the previous forms of DNS security are a suitable
	substitute for DNS cookies, which provide light weight transaction		substitute for DNS cookies, which provide light weight transaction
	authentication of DNS requests and responses with no requirement for		authentication of DNS requests and responses with no requirement for
	pre-configuration.		pre-configuration.
	4. The COOKIE RR		4. The COOKIE OPT option
	COOKIE is a meta-RR that can be included once in the Additional		COOKIE is an OPT RR [RFC2671] option that can be included once in the
	Information portion of DNS requests and responses.		RDATA portion of an OPT RR in DNS requests and responses.
	The RDATA portion of the COOKIE RR is 18 bytes long as shown below.		The option is encoded into 22 bytes as shown below.
			INTERNET-DRAFT DNS Cookies
	1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3		1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
	0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1		0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
			| OPTION-CODE TBD | OPTION-LENGTH = 18 |
			+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Resolver Cookie upper half |		| Resolver Cookie upper half |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Resolver Cookie lower half |		| Resolver Cookie lower half |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Server Cookie upper half |		| Server Cookie upper half |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Server Cookie lower half |		| Server Cookie lower half |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	| Error Code |		| Error Code |
	+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+		+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	The Resolver and Server Cookies are stored in network byte order and		The Resolver and Server Cookies are stored in network byte order and
	are determined as described below.		are determined as described below.
	INTERNET-DRAFT DNS Cookies
	The Error Code field MUST BE zero in requests and in responses unless		The Error Code field MUST BE zero in requests and in responses unless
	the response is communicating a DNS cookie related error. Three		the response is communicating a DNS cookie error. Three values are
	values are possible for Error Code: NOCOOKIE and BADCOOKIE which		possible for Error Code: NOCOOKIE and BADCOOKIE which occur with a
	occur with a Refused RCODE in the DNS response header, and MANYCOOKIE		Refused RCODE in the DNS response header, and MANYCOOKIE which occurs
	which occurs with a FormErr RCODE in the DNS header. More information		with a FormErr RCODE in the DNS header. More information on the
	on the generation of error response appears in Section 5 below.		generation of error response appears in Section 5 below.
	4.1 Resolver Cookies		4.1 Resolver Cookies
	The Resolver Cookie, when it occurs in a COOKIE RR in a DNS response,		The Resolver Cookie, when it occurs in an OPT in a DNS response, is
	is intended to weakly assure the resolver that the response came from		intended to weakly assure the resolver that the response came from a
	a server at the indicated source IP address.		server at the indicated source IP address.
	Servers remember the Resolver Cookie that appears in a query long		Servers remember the Resolver Cookie that appears in a query long
	enough to use it in the construction of the COOKIE RR in the		enough to use it in the construction of the COOKIE OPT option in the
	corresponding response if such a COOKIE RR is included in that		corresponding response if such a COOKIE OPT option is included in
	response.		that response.
	The Resolver Cookie SHOULD be a pseudo-random function of the server		The Resolver Cookie SHOULD be a pseudo-random function of the server
	IP address and a secret quantity known only to the resolver. This		IP address and a secret quantity known only to the resolver. This
	resolver secret SHOULD have 64 bits of entropy [RFC 4086] and MAY be		resolver secret SHOULD have 64 bits of entropy [RFC4086] and MAY be
	changed periodically. The RECOMMENDED method is the HMAC-MD5-64 [RFC		changed periodically. The RECOMMENDED method is the HMAC-MD5-64
	1321], [RFC 2104] of the server IP address and the resolver secret.		[RFC1321], [RFC2104] of the server IP address and the resolver
	That is		secret. That is
	Resolver Cookie =		Resolver Cookie =
	Truncate-64 ( HMAC-MD5 ( Server IP, Resolver Secret ) )		Truncate-64 ( HMAC-MD5 ( Server IP, Resolver Secret ) )
	A resolver MUST NOT use the same Resolver Cookie value for queries to		A resolver MUST NOT use the same Resolver Cookie value for queries to
			INTERNET-DRAFT DNS Cookies
	all servers.		all servers.
	4.2 Server Cookies		4.2 Server Cookies
	The Server Cookie, when it occurs in a COOKIE RR in a query, is		The Server Cookie, when it occurs in a COOKIE OPT option in a query,
	intended to weakly assure the server that the query legitimately came		is intended to weakly assure the server that the query legitimately
	from a resolver at the indicated source IP address that is using the		came from a resolver at the indicated source IP address that is using
	indicated Resolver Cooker.		the indicated Resolver Cookie.
	Resolvers learn Server Cookies and retain them as soft state		Resolvers learn Server Cookies and retain them as soft state
	associated with the server IP address. They learn them from the		associated with the server IP address. They learn them from the
	Server Cookie that appears in the COOKIE RR of a reply that also has		Server Cookie that appears in the COOKIE OPT option of a reply that
	the correct Resolver Cookie, even if that reply is an error message.		also has the correct Resolver Cookie, even if that reply is an error
			message.
	The Server Cookie SHOULD be a pseudo-random function of the request		The Server Cookie SHOULD be a pseudo-random function of the request
	source IP address, the request Resolver Cookie, and a secret quantity		source IP address, the request Resolver Cookie, and a secret quantity
	known only to the server. This server secret SHOULD have 64 bits of		known only to the server. This server secret SHOULD have 64 bits of
			entropy [RFC4086] and SHOULD be changed periodically such as daily.
	INTERNET-DRAFT DNS Cookies		The RECOMMENDED method is the HMAC-MD5-64 [RFC1321], [RFC2104] of the
			request IP address, the Resolver Cookie, and the server secret. That
	entropy [RFC 4086] and SHOULD be changed periodically such as daily.		is
	The RECOMMENDED method is the HMAC-MD5-64 [RFC 1321], [RFC 2104] of
	the request IP address, the Resolver Cookie, and the server secret.
	That is
	Server Cookie = Truncate-64 (		Server Cookie = Truncate-64 (
	HMAC-MD5 ( (Request IP | Resolver Cookie), Server Secret ) )		HMAC-MD5 ( (Request IP | Resolver Cookie), Server Secret ) )
	where "|" represents concatenation. A server MUST NOT use the same		where "|" represents concatenation.
	Server Cookie value for responses to all requests.
			A server MUST NOT use the same Server Cookie value for responses to
			all requests.
	5. General Policies and Implementation		5. General Policies and Implementation
	DNS resolvers and servers will adopt one of three policies regarding		DNS resolvers and servers will adopt one of various policies
	cookies. These policies SHOULD be logically settable on a per server		regarding cookies. These policies SHOULD be logically settable on a
	IP address basis for resolvers and a per resolver IP address,		per server IP address basis for resolvers and a per resolver ( IP
	Resolver Cookie pair for servers. Thus a resolver can have different		address, Resolver Cookie ) pair for servers. Thus a resolver can
	policies for different servers, based on the server IP address. And a		have different policies for different servers, based on the server IP
	server can have different policies for different resolvers, based on		address. And a server can have different policies for different
	the resolver IP address and Resolver Cookie. Of course, the actual		resolvers, based on the resolver IP address and Resolver Cookie. Of
	implementation of setting these policies may by for blocks of values		course, the actual implementation of setting these policies may by
	or use sparse array techniques.		for blocks or classes of values or use sparse array techniques.
	The policy for each value is either "Disabled", "Enabled", or		The policy for each value is either "Disabled", "Enabled", or
	"Enforced" as described below.		"Enforced" as described below.
			INTERNET-DRAFT DNS Cookies
	5.1 Resolver Policies and Implementation		5.1 Resolver Policies and Implementation
	Disabled:		Disabled:
	Never include a COOKIE RR in requests.		Never include a COOKIE RR in requests.
	Ignore COOKIE RRs in the Additional Information section of		Ignore COOKIE OPT options in responses.
	responses.
	Enabled:		Enabled:
	Always include a COOKIE RR in the Additional Information section		Always include an OPT RR with a COOKIE option in requests. If a
	of requests. If a cached Server Cookie for the server is not		cached Server Cookie for the server is not available, the
	available, the Server Cookie field can be set to any value.		Server Cookie field can be set to any value.
	Normally process responses without a COOKIE RR.		Normally process responses without a COOKIE OPT option.
	Silently ignore responses with more than one COOKIE RR.		Silently ignore responses with more than one COOKIE OPT option.
	Silently ignore responses with one COOKIE RR if that RR has an		Silently ignore responses with one COOKIE OPT option if it has an
	incorrect Resolver Cookie value.		incorrect Resolver Cookie value.
	On receipt of a response with one COOKIE RR and that RR having the		On receipt of a response with one COOKIE OPT option and it having
	correct Resolver Cookie value (even if it is a BADCOOKIE error		the correct Resolver Cookie value (even if it is a BADCOOKIE
	response), perform normal response processing, including		error response), perform normal response processing, including
	caching the received Server Cookie and MUST change to the		caching the received Server Cookie and MUST change to the
	Enforced policy for DNS requests to that server IP address.		Enforced policy for DNS requests to that server IP address.
	INTERNET-DRAFT DNS Cookies
	This policy change SHOULD be treated as soft state with the		This policy change SHOULD be treated as soft state with the
	same discard policy as the Server Cookie value for that server.		same discard policy as the Server Cookie value for that server.
	On discarding that state information, the policy for that		On discarding that state information, the policy for that
	server reverts to Enabled.		server reverts to Enabled.
	Enforced:		Enforced:
	Always include a COOKIE RR in the Additional Information section		Always include a COOKIE OPT option in requests.
	of requests.
	Silently ignore all responses that do not include exactly one		Silently ignore all responses that do not include exactly one
	COOKIE RR with that RR having the correct Resolver Cookie		COOKIE OPT option with it having the correct Resolver Cookie
	value. Normally process responses which do include such a		value. Normally process responses which do include such a
	COOKIE RR.		COOKIE OPT option.
	5.2 Server Policies and Implementation		5.2 Server Policies and Implementation
	Disabled:		Disabled:
	Ignore COOKIE RRs in requests.		Ignore COOKIE OPT options in requests.
	Never include a COOKIE RR in responses.		Never include a COOKIE OPT option in responses.
	Enabled:		Enabled:
	Normally process requests without a COOKIE RR.		Normally process requests without a COOKIE OPT option.
	Ignore, other than sending a MANYCOOKIE error response, any		Ignore, other than sending a MANYCOOKIE error response, any
	request with more than one COOKIE RR.		request with more than one COOKIE OPT option.
	Ignore, other than sending a BADCOOKIE error response, any query		Ignore, other than sending a BADCOOKIE error response, any query
	with one COOKIE RR if that RR has an incorrect Server Cookie.		with one COOKIE OPT option if it has an incorrect Server
	On receipt of a request with a COOKIE RR having the correct Server		Cookie.
	Cookie value, perform normal request processing and SHOULD		On receipt of a request with a COOKIE OPT option having the
	adopt the Enforced policy for DNS requests from that resolver		correct Server Cookie value, perform normal request processing
	IP address with the Resolver Cookie in the request. This policy		and SHOULD adopt the Enforced policy for DNS requests from that
	change for that resolver SHOULD be treated as soft state. On		resolver IP address with that Resolver Cookie in the request.
	discarding that state information, the policy for that resolver
	IP and Resolver Cookie pair reverts to enabled.
	Always include a COOKIE RR in responses.
	Enforced:
	Ignore requests without a COOKIE RR or with more than one COOKIE
	RR, other than sending a NOCOOKIE or MANYCOOKIE error message
	respectively.
	Ignore requests with one COOKIE RR if that RR has an incorrect
	Server Cookie, other than sending a BADCOOKIE error message.
	If a request has one COOKIE RR with a correct Server Cookie,
	perform normal processing of the request.
	Include a COOKIE RR in all responses.
	INTERNET-DRAFT DNS Cookies		INTERNET-DRAFT DNS Cookies
			This policy change for that resolver SHOULD be treated as soft
			state. On discarding that state information, the policy for
			that resolver IP and Resolver Cookie pair reverts to enabled.
			Always include a COOKIE OPT option in responses.
			Enforced:
			Ignore requests without a COOKIE OPT option or with more than one
			COOKIE OPT option, other than sending a NOCOOKIE or MANYCOOKIE
			error respectively.
			Ignore requests with one COOKIE OPT option if they have an
			incorrect Server Cookie, other than sending a BADCOOKIE error
			message.
			If a request has one COOKIE OPT option with a correct Server
			Cookie, perform normal processing of the request.
			Include a COOKIE OPT option in all responses.
	5.3 Implementation Requirements		5.3 Implementation Requirements
	DNS resolvers and servers MUST implement DNS cookies.		DNS resolvers and servers MUST implement DNS cookies.
	DNS resolvers SHOULD operate in and be shipped so as to default to		DNS resolvers SHOULD operate in and be shipped so as to default to
	the Enabled or Enforced mode for all servers.		the Enabled or Enforced mode for all servers.
	DNS servers SHOULD operate in and be shipped so as to default to the		DNS servers SHOULD operate in and be shipped so as to default to the
	Enabled or Enforced mode for all resolvers they are willing to		Enabled or Enforced mode for all resolvers they are willing to
	service.		service.
	skipping to change at page 10, line 28 ¶		skipping to change at page 10, line 44 ¶
	6. NAT and AnyCast Considerations		6. NAT and AnyCast Considerations
	In the Classic Internet, DNS Cookies could simply be a pseudo-random		In the Classic Internet, DNS Cookies could simply be a pseudo-random
	function of the resolver IP address and a sever secret or the server		function of the resolver IP address and a sever secret or the server
	IP address and a resolver secret. You would want to compute the		IP address and a resolver secret. You would want to compute the
	Server Cookie that way, so a resolver could cache its Server Cookie		Server Cookie that way, so a resolver could cache its Server Cookie
	for a particular server for an indefinitely amount of time and the		for a particular server for an indefinitely amount of time and the
	server could easily regenerate and check it. You could consider the		server could easily regenerate and check it. You could consider the
	Resolver Cookie to be a resolver signature over the server IP address		Resolver Cookie to be a resolver signature over the server IP address
	which the resolver checks in responses and you could extend this		which the resolver checks in responses and you could extend this
	signature to cover the ID for example.		signature to cover the request ID, for example.
	But we have this wart called NAT [RFC 3022], Network Address		But we have this wart called NAT [RFC3022], Network Address
	Translation (including therein for the purposes of this document NAT-		Translation (including therein for the purposes of this document NAT-
	PT [RFC 2766], Network Address and Protocol Translation). There is no		PT [RFC2766], Network Address and Protocol Translation). There is no
	problem with DNS transactions between resolvers and servers behind a		problem with DNS transactions between resolvers and servers behind a
	NAT box using local IP addresses. Nor is there a problem with NAT		NAT box using local IP addresses. Nor is there a problem with NAT
	translation of internal addresses to external addresses or		translation of internal addresses to external addresses or
	translations between IPv4 and IPv6 addresses, as long as the address		translations between IPv4 and IPv6 addresses, as long as the address
			INTERNET-DRAFT DNS Cookies
	mapping is relatively stable. Should an internal resolver being		mapping is relatively stable. Should an internal resolver being
	mapped to a particular external IP address change occasionally, the		mapped to a particular external IP address change occasionally, the
	disruption is no more than when a resolver rolls-over its DNS COOKIE		disruption is no more than when a resolver rolls-over its DNS COOKIE
	secret. And normally external access to a DNS server behind a NAT box		secret. And normally external access to a DNS server behind a NAT box
	is handled by a fixed mapping which forwards externally received DNS		is handled by a fixed mapping which forwards externally received DNS
	requests to a specific host.		requests to a specific host.
	However, NAT devices sometimes also map ports. This can cause		However, NAT devices sometimes also map ports. This can cause
	multiple DNS requests and responses from multiple internal hosts to		multiple DNS requests and responses from multiple internal hosts to
	be simultaneously mapped to a smaller number of external IP		be simultaneously mapped to a smaller number of external IP
	addresses, frequently one. There could be many resolvers behind a		addresses, frequently one. There could be many resolvers behind a
	NAT box that appear to come from the same source IP address to a		NAT box that appear to come from the same source IP address to a
	server outside that NAT box.. If one of these were an attacker		server outside that NAT box.. If one of these were an attacker
	(think Zombie or Botnet), that behind-NAT attacked could get the		(think Zombie or Botnet), that behind-NAT attacked could get the
	Server Cookie for some server for the outgoing IP address by just		Server Cookie for some server for the outgoing IP address by just
	making some random request to that server. It could then include that		making some random request to that server. It could then include that
	Server Cookie in the COOKIE RR of requests to the server with the		Server Cookie in the COOKIE RR of requests to the server with the
	forged IP address of the local IP address of some other host and/or		forged IP address of the local IP address of some other host and/or
	INTERNET-DRAFT DNS Cookies
	resolver behind the NAT box. (Attacker possession of this Server		resolver behind the NAT box. (Attacker possession of this Server
	Cookie will not help in forging responses to cause cache poisoning as		Cookie will not help in forging responses to cause cache poisoning as
	such responses are protected by the required Resolver Cookie.)		such responses are protected by the required Resolver Cookie.)
	To fix this potential defect, it is necessary to distinguish		To fix this potential defect, it is necessary to distinguish
	different resolvers behind a NAT box from the point of view of the		different resolvers behind a NAT box from the point of view of the
	server. It is for this reason that the Server Cookie is specified as		server. It is for this reason that the Server Cookie is specified as
	a pseudo-random function of both the request source IP address and		a pseudo-random function of both the request source IP address and
	the Resolver Cookie. From this inclusion of the Resolver Cookie in		the Resolver Cookie. From this inclusion of the Resolver Cookie in
	the calculation of the Server Cookie, it follows that a stable		the calculation of the Server Cookie, it follows that a stable
	skipping to change at page 11, line 40 ¶		skipping to change at page 12, line 5 ¶
	cause queries to a DNS server at an IP address to be delivered to any		cause queries to a DNS server at an IP address to be delivered to any
	one of several machines. (External queries to a DNS server behind a		one of several machines. (External queries to a DNS server behind a
	NAT box usually occur via port forwarding such that all such queries		NAT box usually occur via port forwarding such that all such queries
	go to one host.) However, it is impossible to solve this the way the		go to one host.) However, it is impossible to solve this the way the
	similar problem was solved for NATed resolvers; if the Server Cookie		similar problem was solved for NATed resolvers; if the Server Cookie
	was included in the calculation of the Resolver Cookie the same way		was included in the calculation of the Resolver Cookie the same way
	the Resolver Cookie is included in the Server Cookie, you would just		the Resolver Cookie is included in the Server Cookie, you would just
	get an almost infinite series of BADCOOKIE errors as a query was		get an almost infinite series of BADCOOKIE errors as a query was
	repeatedly retried.		repeatedly retried.
			INTERNET-DRAFT DNS Cookies
	For server accessed via anycast or similar mechanisms to successfully		For server accessed via anycast or similar mechanisms to successfully
	support DNS COOKIES, the server clones must either all use the same		support DNS COOKIES, the server clones must either all use the same
	server secret or the mechanism that distributes queries to them must		server secret or the mechanism that distributes queries to them must
	cause the queries from a particular resolver to go to a particular		cause the queries from a particular resolver to go to a particular
	server for a sufficiently long period of time that extra queries due		server for a sufficiently long period of time that extra queries due
	to changes in Server Cookie resulting from accessing different server		to changes in Server Cookie resulting from accessing different server
	machines are not unduly burdensome. Such anycast accessed servers are		machines are not unduly burdensome. When such anycast accessed
	unlikely to be recursive servers or otherwise act as resolvers due to		servers act as recursive servers or otherwise act as resolvers they
	the confusion that would result in getting responses to their queries		normally use a different unique address to source their queries and
	back to the right machine. If they are they must all use the same		avoid confusion in the delivery of responses.
	resolver secret.
	INTERNET-DRAFT DNS Cookies		For simplicity, it is recommended that the same server secret be used
			by each set of anycast servers.
	7. IANA Considerations		7. IANA Considerations
	The meta-RRTYPE value for COOKIE is (TBD, 248 (0xF8) suggested).		The OPT option value for COOKIE is TBD.
	Three new RCODES are assigned values above 15:		Three new RCODES are assigned values above 15:
	NOCOOKIE is assigned the value (TBD, 23 suggested).		NOCOOKIE is assigned the value (TBD, 23 suggested).
	BADCOOKIE is assigned the value (TBD, 24 suggested).		BADCOOKIE is assigned the value (TBD, 24 suggested).
	MANYCOOKIE is assigned the value (TBD, 25 suggested).		MANYCOOKIE is assigned the value (TBD, 25 suggested).
	8. Security Considerations		8. Security Considerations
	DNS Cookies provide a weak form of authentication of DNS requests and		DNS Cookies provide a weak form of authentication of DNS requests and
	responses. In particular, they provide no protection at all against		responses. In particular, they provide no protection at all against
	"on-path" adversaries; that is, they provide no protection against		"on-path" adversaries; that is, they provide no protection against
	any adversary which can observe the plain text DNS traffic, such as		any adversary which can observe the plain text DNS traffic, such as
	an on-path router, bridge, or any device on an on-path shared link		an on-path router, bridge, or any device on an on-path shared link
	unless the DNS traffic in question on that link is appropriately		(unless the DNS traffic in question on that path is appropriately
	encrypted.		encrypted).
	For example, if a host is connected via an unsecured IEEE 802.11 link		For example, if a host is connected via an unsecured IEEE 802.11 link
	(Wi-Fi), any device in the vicinity that could receive and decode the		(Wi-Fi), any device in the vicinity that could receive and decode the
	802.11 transmissions must be considered "on-path". On the other hand,		802.11 transmissions must be considered "on-path". On the other hand,
	in a similar situation but one where 802.11i security is		in a similar situation but one where 802.11i security is
	appropriately deployed, of the Wi-Fi network nodes, only the Access		appropriately deployed on the Wi-Fi network nodes, only the Access
	Point via which the host is connecting is "on-path".		Point via which the host is connecting is "on-path".
	Despite these limitations, use of DNS Cookies on the global Internet		Despite these limitations, use of DNS Cookies on the global Internet
	are expected to provide a significant reduction in the available		are expected to provide a reduction in the available launch points
	launch points for the traffic amplification and denial of service		for the traffic amplification and denial of service attacks described
	attacks described in Section 2 above.		in Section 2 above.
	The recommended cryptographic algorithm for use in DNS Cookies is		The recommended cryptographic algorithm for use in DNS Cookies is
	HMAC-MD5-64, that is, the HMAC scheme [RFC 2104] using the MD5 hash
	function [RFC 1321] with its output truncated to 64-bits. Although		INTERNET-DRAFT DNS Cookies
	MD5 is now considered to be susceptible to collisions attacks, this
	does not effect the security of HMAC-MD5.		HMAC-MD5-64, that is, the HMAC scheme [RFC2104] using the MD5 hash
			function [RFC1321] with its output truncated to 64-bits. Although MD5
			is now considered to be susceptible to collisions attacks, this does
			not effect the security of HMAC-MD5.
	In light of the weak plain-text token security provided by DNS		In light of the weak plain-text token security provided by DNS
	Cookies, stronger cryptography is probably not warranted. However,		Cookies, stronger cryptography is probably not warranted. However,
	there is nothing wrong with using, for example, HMAC-SHA256-64		there is nothing wrong with using, for example, HMAC-SHA256-64
	instead, assuming a DNS processor has adequate computational		instead, assuming a DNS processor has adequate computational
	resources available. DNS processors that feel the need for somewhat		resources available. DNS processors that feel the need for somewhat
	stronger security without a significant increase in computational		stronger security without a significant increase in computational
	load should consider more frequent changes in their resolver and/or		load should consider more frequent changes in their resolver and/or
	server secret; however, this does require more frequent generation of		server secret; however, this does require more frequent generation of
	a cryptographically strong random number [RFC 4086] and a change in a		a cryptographically strong random number [RFC4086] and a change in a
	server secret will result in a number of BADCOOKIE rejected requests		server secret will result in a number of BADCOOKIE rejected requests
	from resolvers caching their old Server Cookie.		from resolvers caching their old Server Cookie.
	INTERNET-DRAFT DNS Cookies
	9. Copyright and Disclaimer		9. Copyright and Disclaimer
	Copyright (C) The Internet Society (2006).		Copyright (C) The Internet Society (2006).
	This document is subject to the rights, licenses and restrictions		This document is subject to the rights, licenses and restrictions
	contained in BCP 78, and except as set forth therein, the authors		contained in BCP 78, and except as set forth therein, the authors
	retain all their rights.		retain all their rights.
	This document and the information contained herein are provided on an		This document and the information contained herein are provided on an
	"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS		"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
	OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET		OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY AND THE INTERNET
	ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,		ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED,
	INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE		INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE
	INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED		INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
	WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.		WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
	10. Normative References		10. Normative References
	[RFC 1321] - Rivest, R., "The MD5 Message-Digest Algorithm", RFC		[RFC1321] - Rivest, R., "The MD5 Message-Digest Algorithm", RFC 1321,
	1321, April 1992.		April 1992.
	[RFC 2104] - Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-		[RFC2104] - Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
	Hashing for Message Authentication", RFC 2104, February 1997.		Hashing for Message Authentication", RFC 2104, February 1997.
	[RFC 2119] - Bradner, S., "Key words for use in RFCs to Indicate		[RFC2119] - Bradner, S., "Key words for use in RFCs to Indicate
	Requirement Levels", BCP 14, RFC 2119, March 1997.		Requirement Levels", BCP 14, RFC 2119, March 1997.
	[RFC 2181] - Elz, R. and R. Bush, "Clarifications to the DNS		[RFC2181] - Elz, R. and R. Bush, "Clarifications to the DNS
			INTERNET-DRAFT DNS Cookies
	Specification", RFC 2181, July 1997.		Specification", RFC 2181, July 1997.
	[RFC 4086] - Eastlake, D., 3rd, Schiller, J., and S. Crocker,		[RFC2671] - Vixie, P., "Extension Mechanisms for DNS (EDNS0)", August
			1999.
			[RFC4086] - Eastlake, D., 3rd, Schiller, J., and S. Crocker,
	"Randomness Requirements for Security", BCP 106, RFC 4086, June 2005.		"Randomness Requirements for Security", BCP 106, RFC 4086, June 2005.
	[STD 13]		[STD13]
	Mockapetris, P., "Domain names - concepts and facilities", STD		Mockapetris, P., "Domain names - concepts and facilities", STD
	13, RFC 1034, November 1987.		13, RFC 1034, November 1987.
	Mockapetris, P., "Domain names - implementation and		Mockapetris, P., "Domain names - implementation and
	specification", STD 13, RFC 1035, November 1987.		specification", STD 13, RFC 1035, November 1987.
	11. Informative References.		11. Informative References.
	[RFC 2845] - Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B.		[RFC2766] - Tsirtsis, G., P. Srisuresh"Network Address Translation -
			Protocol Translation (NAT-PT)", February 2000.
			[RFC2845] - Vixie, P., Gudmundsson, O., Eastlake 3rd, D., and B.
	Wellington, "Secret Key Transaction Authentication for DNS (TSIG)",		Wellington, "Secret Key Transaction Authentication for DNS (TSIG)",
	RFC 2845, May 2000.		RFC 2845, May 2000.
	INTERNET-DRAFT DNS Cookies		[RFC2930] - Eastlake 3rd, D., "Secret Key Establishment for DNS (TKEY
			RR)", RFC 2930, September 2000.
	[RFC 2930] - Eastlake 3rd, D., "Secret Key Establishment for DNS
	(TKEY RR)", RFC 2930, September 2000.
	[RFC 2931] - Eastlake 3rd, D., "DNS Request and Transaction		[RFC2931] - Eastlake 3rd, D., "DNS Request and Transaction Signatures
	Signatures ( SIG(0)s )", RFC 2931, September 2000.		( SIG(0)s )", RFC 2931, September 2000.
	[RFC 3022] - Srisuresh, P. and K. Egevang, "Traditional IP Network		[RFC3022] - Srisuresh, P. and K. Egevang, "Traditional IP Network
	Address Translator (Traditional NAT)", RFC 3022, January 2001.		Address Translator (Traditional NAT)", RFC 3022, January 2001.
	[RFC 4033] - Arends, R., Austein, R., Larson, M., Massey, D., and S.		[RFC4033] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
	Rose, "DNS Security Introduction and Requirements", RFC 4033, March		Rose, "DNS Security Introduction and Requirements", RFC 4033, March
	2005.		2005.
	[RFC 4034] - Arends, R., Austein, R., Larson, M., Massey, D., and S.		[RFC4034] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
	Rose, "Resource Records for the DNS Security Extensions", RFC 4034,		Rose, "Resource Records for the DNS Security Extensions", RFC 4034,
	March 2005.		March 2005.
	[RFC 4035] - Arends, R., Austein, R., Larson, M., Massey, D., and S.		[RFC4035] - Arends, R., Austein, R., Larson, M., Massey, D., and S.
	Rose, "Protocol Modifications for the DNS Security Extensions", RFC		Rose, "Protocol Modifications for the DNS Security Extensions", RFC
	4035, March 2005.		4035, March 2005.
	INTERNET-DRAFT DNS Cookies		INTERNET-DRAFT DNS Cookies
	Author's Address		Author's Address
	Donald E. Eastlake 3rd		Donald E. Eastlake 3rd
	Motorola Laboratories		Motorola Laboratories
	155 Beaver Street		111 Locke Drive
	Milford, MA 01757 USA		Marlborough, MA 01752 USA
	Telephone: +1-508-786-7554 (w)		Telephone: +1-508-786-7554 (w)
	EMail: Donald.Eastlake@motorola.com		EMail: Donald.Eastlake@motorola.com
	Additional IPR Provisions		Additional IPR Provisions
	The IETF takes no position regarding the validity or scope of any		The IETF takes no position regarding the validity or scope of any
	Intellectual Property Rights or other rights that might be claimed		Intellectual Property Rights or other rights that might be claimed
	to pertain to the implementation or use of the technology		to pertain to the implementation or use of the technology
	skipping to change at page 15, line 44 ¶		skipping to change at page 15, line 44 ¶
	at http://www.ietf.org/ipr.		at http://www.ietf.org/ipr.
	The IETF invites any interested party to bring to its attention		The IETF invites any interested party to bring to its attention
	any copyrights, patents or patent applications, or other		any copyrights, patents or patent applications, or other
	proprietary rights that may cover technology that may be required		proprietary rights that may cover technology that may be required
	to implement this standard. Please address the information to the		to implement this standard. Please address the information to the
	IETF at ietf-ipr@ietf.org.		IETF at ietf-ipr@ietf.org.
	Expiration and File Name		Expiration and File Name
	This draft expires in December 2006.		This draft expires in April 2007.
	Its file name is draft-eastlake-dnsext-cookies-00.txt		Its file name is draft-eastlake-dnsext-cookies-01.txt
End of changes. 83 change blocks.
	170 lines changed or deleted		189 lines changed or added
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