draft-ietf-uta-email-tls-certs-08.txt		draft-ietf-uta-email-tls-certs-09.txt
	Network Working Group A. Melnikov		Network Working Group A. Melnikov
	Internet-Draft Isode Ltd		Internet-Draft Isode Ltd
	Updates: 2595, 3207, 3501, 5804 (if December 17, 2015		Updates: 2595, 3207, 3501, 5804 (if December 29, 2015
	approved)		approved)
	Intended status: Standards Track		Intended status: Standards Track
	Expires: June 19, 2016		Expires: July 1, 2016
	Updated TLS Server Identity Check Procedure for Email Related Protocols		Updated TLS Server Identity Check Procedure for Email Related Protocols
	draft-ietf-uta-email-tls-certs-08		draft-ietf-uta-email-tls-certs-09
	Abstract		Abstract
	This document describes TLS server identity verification procedure		This document describes TLS server identity verification procedure
	for SMTP Submission, IMAP, POP and ManageSieve clients. It replaces		for SMTP Submission, IMAP, POP and ManageSieve clients. It replaces
	Section 2.4 of RFC 2595, updates Section 4.1 of RFC 3207, updates		Section 2.4 of RFC 2595, updates Section 4.1 of RFC 3207, updates
	Section 11.1 of RFC 3501, updates Section 2.2.1 of RFC 5804.		Section 11.1 of RFC 3501, updates Section 2.2.1 of RFC 5804.
	Status of This Memo		Status of This Memo
	skipping to change at page 1, line 35		skipping to change at page 1, line 35
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF). Note that other groups may also distribute		Task Force (IETF). Note that other groups may also distribute
	working documents as Internet-Drafts. The list of current Internet-		working documents as Internet-Drafts. The list of current Internet-
	Drafts is at http://datatracker.ietf.org/drafts/current/.		Drafts is at http://datatracker.ietf.org/drafts/current/.
	Internet-Drafts are draft documents valid for a maximum of six months		Internet-Drafts are draft documents valid for a maximum of six months
	and may be updated, replaced, or obsoleted by other documents at any		and may be updated, replaced, or obsoleted by other documents at any
	time. It is inappropriate to use Internet-Drafts as reference		time. It is inappropriate to use Internet-Drafts as reference
	material or to cite them other than as "work in progress."		material or to cite them other than as "work in progress."
	This Internet-Draft will expire on June 19, 2016.		This Internet-Draft will expire on July 1, 2016.
	Copyright Notice		Copyright Notice
	Copyright (c) 2015 IETF Trust and the persons identified as the		Copyright (c) 2015 IETF Trust and the persons identified as the
	document authors. All rights reserved.		document authors. All rights reserved.
	This document is subject to BCP 78 and the IETF Trust's Legal		This document is subject to BCP 78 and the IETF Trust's Legal
	Provisions Relating to IETF Documents		Provisions Relating to IETF Documents
	(http://trustee.ietf.org/license-info) in effect on the date of		(http://trustee.ietf.org/license-info) in effect on the date of
	publication of this document. Please review these documents		publication of this document. Please review these documents
	skipping to change at page 2, line 13		skipping to change at page 2, line 13
	include Simplified BSD License text as described in Section 4.e of		include Simplified BSD License text as described in Section 4.e of
	the Trust Legal Provisions and are provided without warranty as		the Trust Legal Provisions and are provided without warranty as
	described in the Simplified BSD License.		described in the Simplified BSD License.
	Table of Contents		Table of Contents
	1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2		1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
	2. Conventions Used in This Document . . . . . . . . . . . . . . 3		2. Conventions Used in This Document . . . . . . . . . . . . . . 3
	3. Email Server Certificate Verification Rules . . . . . . . . . 3		3. Email Server Certificate Verification Rules . . . . . . . . . 3
	4. Compliance Checklist for Certification Authorities . . . . . 5		4. Compliance Checklist for Certification Authorities . . . . . 5
	4.1. Notes on handling of SRV-ID by Certification Authorities 5		4.1. Notes on handling of delegated email services by
			Certification Authorities . . . . . . . . . . . . . . . . 5
	5. Compliance Checklist for Mail Service Providers and		5. Compliance Checklist for Mail Service Providers and
	Certificate Signing Request generation tools . . . . . . . . 6		Certificate Signing Request generation tools . . . . . . . . 6
	5.1. Notes on hosting multiple domains . . . . . . . . . . . . 6		5.1. Notes on hosting multiple domains . . . . . . . . . . . . 7
	6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 7		6. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 8
	7. Operational Considerations . . . . . . . . . . . . . . . . . 8		7. Operational Considerations . . . . . . . . . . . . . . . . . 9
	8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8		8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
	9. Security Considerations . . . . . . . . . . . . . . . . . . . 9		9. Security Considerations . . . . . . . . . . . . . . . . . . . 9
	10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9		10. References . . . . . . . . . . . . . . . . . . . . . . . . . 9
	10.1. Normative References . . . . . . . . . . . . . . . . . . 9		10.1. Normative References . . . . . . . . . . . . . . . . . . 9
	10.2. Informative References . . . . . . . . . . . . . . . . . 10		10.2. Informative References . . . . . . . . . . . . . . . . . 11
	Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 12		Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . 12
	Appendix B. Changes since draft-ietf-uta-email-tls-certs-00 . . 12		Appendix B. Changes to RFC 2595, RFC 3207, RFC 3501, RFC 5804 . 12
	Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 12		Appendix C. Changes since draft-ietf-uta-email-tls-certs-00 . . 13
			Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 13
	1. Introduction		1. Introduction
	Use of TLS by SMTP Submission, IMAP, POP and ManageSieve clients is		Use of TLS by SMTP Submission, IMAP, POP and ManageSieve clients is
	described in [RFC3207], [RFC3501], [RFC2595] and [RFC5804]		described in [RFC3207], [RFC3501], [RFC2595] and [RFC5804]
	respectively. Each of the documents describes slightly different		respectively. Each of the documents describes slightly different
	rules for server certificate identity verification (or doesn't define		rules for server certificate identity verification (or doesn't define
	any rules at all). In reality, email client and server developers		any rules at all). In reality, email client and server developers
	implement many of these protocols at the same time, so it would be		implement many of these protocols at the same time, so it would be
	good to define modern and consistent rules for verifying email server		good to define modern and consistent rules for verifying email server
	skipping to change at page 3, line 16		skipping to change at page 3, line 18
	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 [RFC2119].		document are to be interpreted as described in [RFC2119].
	The following terms or concepts are used through the document:		The following terms or concepts are used through the document:
	reference identifier: (formally defined in [RFC6125]) One of the		reference identifier: (formally defined in [RFC6125]) One of the
	domain names that the email client (an SMTP, IMAP, POP3 or		domain names that the email client (an SMTP, IMAP, POP3 or
	ManageSieve client) associates with the target email server. For		ManageSieve client) associates with the target email server. For
	some identifier types, the identifier can also include an		some identifier types, the identifier also includes an application
	application service type for performing name checks on the server		service type. Reference identifiers are used for performing name
	certificate. When name checks are applicable, at least one of the		checks on server certificates.
	reference identifiers MUST match an [RFC6125] DNS-ID or SRV-ID (or
	if none are present the [RFC6125] CN-ID) of the server
	certificate.
	CN-ID, DNS-ID, SRV-ID and URI-ID are identifier types (see [RFC6125]		CN-ID, DNS-ID, SRV-ID and URI-ID are identifier types (see [RFC6125]
	for details). For convenience, their short definitions from		for details). For convenience, their short definitions from
	[RFC6125] are listed below:		[RFC6125] are listed below:
	CN-ID = a Relative Distinguished Name (RDN) in the certificate		CN-ID = a Relative Distinguished Name (RDN) in the certificate
	subject field that contains one and only one attribute-type-and-		subject field that contains one and only one attribute-type-and-
	value pair of type Common Name (CN), where the value matches the		value pair of type Common Name (CN), where the value matches the
	overall form of a domain name (informally, dot- separated letter-		overall form of a domain name (informally, dot- separated letter-
	digit-hyphen labels).		digit-hyphen labels).
	skipping to change at page 3, line 48		skipping to change at page 3, line 47
	URI-ID = a subjectAltName entry of type uniformResourceIdentifier		URI-ID = a subjectAltName entry of type uniformResourceIdentifier
	whose value includes both (i) a "scheme" and (ii) a "host"		whose value includes both (i) a "scheme" and (ii) a "host"
	component (or its equivalent) that matches the "reg-name" rule		component (or its equivalent) that matches the "reg-name" rule
	(where the quoted terms represent the associated [RFC5234]		(where the quoted terms represent the associated [RFC5234]
	productions from [RFC3986]).		productions from [RFC3986]).
	3. Email Server Certificate Verification Rules		3. Email Server Certificate Verification Rules
	During a TLS negotiation, an email client (i.e., an SMTP, IMAP, POP3		During a TLS negotiation, an email client (i.e., an SMTP, IMAP, POP3
	or ManageSieve client) MUST check its understanding of the server		or ManageSieve client) MUST check its understanding of the server
	hostname against the server's identity as presented in the server		identity (client's reference identifiers) against the server's
	Certificate message, in order to prevent man-in-the-middle attacks.		identity as presented in the server Certificate message, in order to
	This check is only performed after the server certificate passes		prevent man-in-the-middle attacks. This check is only performed
	certification path validation as described in Section 6 of [RFC5280].		after the server certificate passes certification path validation as
	Matching is performed according to the rules specified in Section 6		described in Section 6 of [RFC5280]. Matching is performed according
	of [RFC6125], including "certificate pinning" and the procedure on		to the rules specified in Section 6 of [RFC6125], including the
	failure to match. The following inputs are used by the verification		relative order of matching of different identifier types,
	procedure used in [RFC6125]:		"certificate pinning" and the procedure on failure to match. The
			following inputs are used by the verification procedure used in
			[RFC6125]:
	1. For DNS-ID and CN-ID identifier types the client MUST use one or		1. For DNS-ID and CN-ID identifier types the client MUST use one or
	more of the following as "reference identifiers": (a) the domain		more of the following as "reference identifiers": (a) the domain
	portion of the user's email address, (b) the hostname it used to		portion of the user's email address, (b) the hostname it used to
	open the connection (without CNAME canonicalization). The client		open the connection (without CNAME canonicalization). The client
	MAY also use (c) a value securely derived from (a) or (b), such		MAY also use (c) a value securely derived from (a) or (b), such
	as using "secure" DNSSEC [RFC4033][RFC4034][RFC4035] validated		as using "secure" DNSSEC [RFC4033][RFC4034][RFC4035] validated
	lookup.		lookup.
	2. When using email service discovery procedure specified in		2. When using email service discovery procedure specified in
	skipping to change at page 5, line 9		skipping to change at page 5, line 11
	certificate. For example, a DNS-ID of *.example.com would match		certificate. For example, a DNS-ID of *.example.com would match
	a.example.com, foo.example.com, etc. but would not match		a.example.com, foo.example.com, etc. but would not match
	example.com. Note that the wildcard character MUST NOT be used		example.com. Note that the wildcard character MUST NOT be used
	as a fragment of the left-most name component (e.g.,		as a fragment of the left-most name component (e.g.,
	*oo.example.com, f*o.example.com, or foo*.example.com).		*oo.example.com, f*o.example.com, or foo*.example.com).
	4. Compliance Checklist for Certification Authorities		4. Compliance Checklist for Certification Authorities
	1. CA MUST support issuance of server certificates with DNS-ID		1. CA MUST support issuance of server certificates with DNS-ID
	identifier type (subjectAltName of dNSName type [RFC5280]).		identifier type (subjectAltName of dNSName type [RFC5280]).
			(Note that some DNS-IDs may refer to domain portions of email
			addresses, so they might not have corresponding A/AAAA DNS
			records.)
	2. CA MUST support issuance of server certificates with SRV-ID		2. CA MUST support issuance of server certificates with SRV-ID
	identifier type (subjectAltName of SRVName type [RFC4985]) for		identifier type (subjectAltName of SRVName type [RFC4985]) for
	each type of email service. See Section 4.1 for more discussion		each type of email service. See Section 4.1 for more discussion
	on what this means for Certification Authorities.		on what this means for Certification Authorities.
	3. For backward compatibility with deployed client base, CA MUST		3. For backward compatibility with deployed client base, CA MUST
	support issuance of server certificates with CN-ID identifier		support issuance of server certificates with CN-ID identifier
	type (CN attribute from the subject name, see [RFC6125]).		type (CN attribute from the subject name, see [RFC6125]).
	4. CA MAY allow "*" (wildcard) as the left-most name component of		4. CA MAY allow "*" (wildcard) as the left-most name component of
	DNS-ID or CN-ID in server certificates it issues.		DNS-ID or CN-ID in server certificates it issues.
	4.1. Notes on handling of SRV-ID by Certification Authorities		4.1. Notes on handling of delegated email services by Certification
			Authorities
	[RFC6186] provides an easy way for organizations to autoconfigure		[RFC6186] provides an easy way for organizations to autoconfigure
	email clients. It also allows for delegation of email services to an		email clients. It also allows for delegation of email services to an
	email hosting provider. When connecting to such delegated hosting		email hosting provider. When connecting to such delegated hosting
	service an email client that attempts to verify TLS server identity		service an email client that attempts to verify TLS server identity
	needs to know that if it connects to imap.hosting.example.net that		needs to know that if it connects to imap.hosting.example.net that
	such server is authorized to provide email access for an email such		such server is authorized to provide email access for an email such
	as alice@example.org. In absence of SRV-IDs, users of compliant		as alice@example.org. In absence of SRV-IDs, users of compliant
	email clients would be forced to manually confirm exception, because		email clients would be forced to manually confirm exception, because
	the TLS server certificate verification procedures specified in this		the TLS server certificate verification procedures specified in this
	document would result in failure to match the TLS server certificate		document would result in failure to match the TLS server certificate
	against the expected domain(s). One way to provide such		against the expected domain(s). One way to provide such
	authorization is for the TLS certificate for imap.hosting.example.net		authorization is for the TLS certificate for imap.hosting.example.net
	to include SRV-ID(s) (or DNS-ID) for the example.org domain.		to include SRV-ID(s) (or DNS-ID) for the example.org domain.
	(Another way is for SRV lookups to be protected by DNSSEC, but this		(Another way is for DNS SRV lookups to be protected by DNSSEC, but
	solution depends on DNSSEC and thus is not discussed in this		this solution depends on ubiquitous use of DNSSEC and availability of
	document. A future update to this document might rectify this.)		DNSSEC-aware APIs and thus is not discussed in this document. A
			future update to this document might rectify this.)
	The ability to issue certificates that contain SRV-ID implies the		A certification authority that receives a Certificate Signing Request
	ability to verify that entities requesting them are authorized to run		containing multiple unrelated DNS-IDs and/or SRV-IDs (e.g. DNS-ID of
	email service for these SRV-IDs. In particular, certification		example.org and DNS-ID of example.com) needs to verify that the
	authorities that can't verify such authorization MUST NOT include		entity that supplied such Certificate Signing Request is authorized
	email SRV-IDs in certificates they issue. This document doesn't		to provide email service for all requested domains.
	specify exact mechanism(s) that can be used to achieve this.
	However, a few special case recommendations are listed below.		The ability to issue certificates that contain an SRV-ID (or a DNS-ID
			for the domain part of email addresses) implies the ability to verify
			that entities requesting them are authorized to run email service for
			these SRV-IDs/DNS-IDs. In particular, certification authorities that
			can't verify such authorization (whether for a particular domain or
			in general) MUST NOT include such email SRV-IDs/DNS-IDs in
			certificates they issue. This document doesn't specify exact
			mechanism(s) that can be used to achieve this. However, a few
			special case recommendations are listed below.
	A certification authority willing to sign a certificate containing a		A certification authority willing to sign a certificate containing a
	particular DNS-ID SHOULD also support signing a certificate		particular DNS-ID SHOULD also support signing a certificate
	containing one or more of email SRV-IDs for the same domain, because		containing one or more of email SRV-IDs for the same domain, because
	the SRV-ID effectively provides more restricted access to an email		the SRV-ID effectively provides more restricted access to an email
	service for the domain (as opposed to unrestricted use of any		service for the domain (as opposed to unrestricted use of any
	services for the same domain, as specified by DNS-ID).		services for the same domain, as specified by DNS-ID).
	A certification authority which also provides DNS service for a		A certification authority which also provides DNS service for a
	domain can use DNS information to validate SRV-IDs for the domain.		domain can use DNS information to validate SRV-IDs/DNS-IDs for the
			domain.
			A certification authority which is also a Mail Service Provider for a
			hosted domain can use that knowdledge to validate SRV-IDs/DNS-IDs for
			the domain.
	5. Compliance Checklist for Mail Service Providers and Certificate		5. Compliance Checklist for Mail Service Providers and Certificate
	Signing Request generation tools		Signing Request generation tools
			Mail Service Providers and Certificate Signing Request generation
			tools
	1. MUST include the DNS-ID identifier type in Certificate Signing		1. MUST include the DNS-ID identifier type in Certificate Signing
	Requests for the host name(s) where the email server(s) are		Requests for the host name(s) where the email server(s) are
	running. SHOULD include the DNS-ID identifier type in		running. They SHOULD include the DNS-ID identifier type in
	Certificate Signing Requests for the domain portion of served		Certificate Signing Requests for the domain portion of served
	email addresses.		email addresses.
	2. If the email services provided are discoverable using DNS SRV as		2. If the email services provided are discoverable using DNS SRV as
	specified in [RFC6186], the Mail Service Provider MUST include		specified in [RFC6186], the Mail Service Provider MUST include
	the SRV-ID identifier type for each type of email service in		the SRV-ID identifier type for each type of email service in
	Certificate Signing Requests.		Certificate Signing Requests.
	3. SHOULD include CN-ID identifier type for the host name where the		3. SHOULD include CN-ID identifier type for the host name where the
	email server(s) is running in Certificate Signing Requests for		email server(s) is running in Certificate Signing Requests for
	skipping to change at page 7, line 23		skipping to change at page 7, line 47
	when the list of domains changes. Use of DNS SRV without SRV-ID		when the list of domains changes. Use of DNS SRV without SRV-ID
	requires manual confirmation from users. While preloading pinned		requires manual confirmation from users. While preloading pinned
	certificates avoids the need for manual confirmation, this		certificates avoids the need for manual confirmation, this
	information can get stale quickly or would require support for a new		information can get stale quickly or would require support for a new
	mechanism for distributing preloaded pinned certificates. A single		mechanism for distributing preloaded pinned certificates. A single
	certificate (the second choice) requires that when a domain is added,		certificate (the second choice) requires that when a domain is added,
	then a new Certificate Signing Request that includes a complete list		then a new Certificate Signing Request that includes a complete list
	of all the domains needs to be issued and passed to a CA in order to		of all the domains needs to be issued and passed to a CA in order to
	generate a new certificate. Separate IP/port can avoid regenerating		generate a new certificate. Separate IP/port can avoid regenerating
	the certificate, but requires more transport layer resources. Use of		the certificate, but requires more transport layer resources. Use of
	TLS SNI requires each email client to support it.		TLS SNI requires each email client to use it.
	Several Mail Service Providers host hundreds and even thousands of		Several Mail Service Providers host hundreds and even thousands of
	domains. This document, as well as its predecessors RFC 2595, RFC		domains. This document, as well as its predecessors RFC 2595, RFC
	3207, RFC 3501 and RFC 5804 don't address scaling issues caused by		3207, RFC 3501 and RFC 5804 don't address scaling issues caused by
	use of TLS in multi-tenanted environments. Further work is needed to		use of TLS in multi-tenanted environments. Further work is needed to
	address this issue, possibly using DNSSEC or something like POSH		address this issue, possibly using DNSSEC or something like POSH
	[RFC7711].		[RFC7711].
	6. Examples		6. Examples
	skipping to change at page 10, line 11		skipping to change at page 10, line 33
	[RFC5804] Melnikov, A., Ed. and T. Martin, "A Protocol for Remotely		[RFC5804] Melnikov, A., Ed. and T. Martin, "A Protocol for Remotely
	Managing Sieve Scripts", RFC 5804, DOI 10.17487/RFC5804,		Managing Sieve Scripts", RFC 5804, DOI 10.17487/RFC5804,
	July 2010, <http://www.rfc-editor.org/info/rfc5804>.		July 2010, <http://www.rfc-editor.org/info/rfc5804>.
	[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,		[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
	Housley, R., and W. Polk, "Internet X.509 Public Key		Housley, R., and W. Polk, "Internet X.509 Public Key
	Infrastructure Certificate and Certificate Revocation List		Infrastructure Certificate and Certificate Revocation List
	(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,		(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
	<http://www.rfc-editor.org/info/rfc5280>.		<http://www.rfc-editor.org/info/rfc5280>.
			[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
			Extensions: Extension Definitions", RFC 6066,
			DOI 10.17487/RFC6066, January 2011,
			<http://www.rfc-editor.org/info/rfc6066>.
	[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and		[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
	Verification of Domain-Based Application Service Identity		Verification of Domain-Based Application Service Identity
	within Internet Public Key Infrastructure Using X.509		within Internet Public Key Infrastructure Using X.509
	(PKIX) Certificates in the Context of Transport Layer		(PKIX) Certificates in the Context of Transport Layer
	Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March		Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
	2011, <http://www.rfc-editor.org/info/rfc6125>.		2011, <http://www.rfc-editor.org/info/rfc6125>.
	[RFC6186] Daboo, C., "Use of SRV Records for Locating Email		[RFC6186] Daboo, C., "Use of SRV Records for Locating Email
	Submission/Access Services", RFC 6186,		Submission/Access Services", RFC 6186,
	DOI 10.17487/RFC6186, March 2011,		DOI 10.17487/RFC6186, March 2011,
	skipping to change at page 11, line 10		skipping to change at page 11, line 36
	[RFC4035] 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		Rose, "Protocol Modifications for the DNS Security
	Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,		Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
	<http://www.rfc-editor.org/info/rfc4035>.		<http://www.rfc-editor.org/info/rfc4035>.
	[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax		[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
	Specifications: ABNF", STD 68, RFC 5234,		Specifications: ABNF", STD 68, RFC 5234,
	DOI 10.17487/RFC5234, January 2008,		DOI 10.17487/RFC5234, January 2008,
	<http://www.rfc-editor.org/info/rfc5234>.		<http://www.rfc-editor.org/info/rfc5234>.
	[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
	Extensions: Extension Definitions", RFC 6066,
	DOI 10.17487/RFC6066, January 2011,
	<http://www.rfc-editor.org/info/rfc6066>.
	[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication		[RFC6698] Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
	of Named Entities (DANE) Transport Layer Security (TLS)		of Named Entities (DANE) Transport Layer Security (TLS)
	Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August		Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
	2012, <http://www.rfc-editor.org/info/rfc6698>.		2012, <http://www.rfc-editor.org/info/rfc6698>.
	[RFC7711] Miller, M. and P. Saint-Andre, "PKIX over Secure HTTP		[RFC7711] Miller, M. and P. Saint-Andre, "PKIX over Secure HTTP
	(POSH)", RFC 7711, DOI 10.17487/RFC7711, November 2015,		(POSH)", RFC 7711, DOI 10.17487/RFC7711, November 2015,
	<http://www.rfc-editor.org/info/rfc7711>.		<http://www.rfc-editor.org/info/rfc7711>.
	Appendix A. Acknowledgements		Appendix A. Acknowledgements
	Thank you to Chris Newman, Viktor Dukhovni, Sean Turner, Russ		Thank you to Chris Newman, Viktor Dukhovni, Sean Turner, Russ
	Housley, Alessandro Vesely, Harald Alvestrand and John Levine for		Housley, Alessandro Vesely, Harald Alvestrand and John Levine for
	comments on this document.		comments on this document.
	The editor of this document copied lots of text from RFC 2595 and RFC		The editor of this document copied lots of text from RFC 2595 and RFC
	6125, so the hard work of editors of these document is appreciated.		6125, so the hard work of editors of these document is appreciated.
	Appendix B. Changes since draft-ietf-uta-email-tls-certs-00		Appendix B. Changes to RFC 2595, RFC 3207, RFC 3501, RFC 5804
			This section lists detailed changes this document applies to RFC
			2595, RFC 3207, RFC 3501 and RFC 5804.
			The entire Section 2.4 of RFC 2595 is replaced with the following
			text:
			During the TLS negotiation, the client checks its understanding of
			the server identity against the provided server's identity as
			specified in Section 3.
			The 3rd paragraph (and its subparagraphs) in Section 11.1 of RFC 3501
			is replaced with the following text:
			During the TLS negotiation, the IMAP client checks its
			understanding of the server identity against the provided server's
			identity as specified in Section 3.
			The 3rd paragraph (and its subparagraphs) in Section 4.1 of RFC 3207
			is replaced with the following text:
			During the TLS negotiation, the Submission client checks its
			understanding of the server identity against the provided server's
			identity as specified in Section 3.
			Sections 2.2.1 and 2.2.1.1 of RFC 5804 are replaced with the
			following text:
			During the TLS negotiation, the ManageSieve client checks its
			understanding of the server identity against the server's identity
			as specified in Section 3. When the reference identity is an IP
			address, the iPAddress subjectAltName SHOULD be used by the client
			for comparison. The comparison is performed as described in
			Section 2.2.1.2 of RFC 5804.
			Appendix C. Changes since draft-ietf-uta-email-tls-certs-00
	[[Note to RFC Editor: Please delete this section before publication]]		[[Note to RFC Editor: Please delete this section before publication]]
	Added another example, clarified that subjectAltName and DNS SRV are		Added another example, clarified that subjectAltName and DNS SRV are
	using slightly different syntax.		using slightly different syntax.
	As any certificate can only include one CN-ID, corrected examples.		As any certificate can only include one CN-ID, corrected examples.
	Split rules to talk seperately about requirements on MUAs, CAs and		Split rules to talk seperately about requirements on MUAs, CAs and
	MSPs/CSR generation tools.		MSPs/CSR generation tools.
End of changes. 21 change blocks.
	46 lines changed or deleted		104 lines changed or added
This html diff was produced by rfcdiff 1.42. The latest version is available from http://tools.ietf.org/tools/rfcdiff/