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
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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-
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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
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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
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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).
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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
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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
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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
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[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. 
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