[ietf-smtp] Review of draft-moore-email-tls-00.txt
Alexey Melnikov <alexey.melnikov@isode.com> Thu, 31 October 2013 17:22 UTC
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From: Alexey Melnikov <alexey.melnikov@isode.com>
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To: Keith Moore <moore@network-heretics.com>
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Cc: ietf-smtp@ietf.org
Subject: [ietf-smtp] Review of draft-moore-email-tls-00.txt
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Hi Keith, I am glad to see your draft. Some specific comments: 2.1. Mail Server Requirements The following requirements apply to IMAP, POP, and Submission server implementations: All IMAP, POP, and Submission servers MUST be configurable to support the use of TLS and the Implicit TLS mechanism when communicating with MUAs. While reading your document I was wondering where the secure submission is defined. Then I finally found a request for a new port in the IANA considerations section. Several MUAs and multiple MSPs implement secure submission on port 465. This was never document and is not registered. (I think this was a Microsoft invention, but I don't know exact history.) The port is officially assigned to another protocol. There are a couple of problems with that. One is trying to register unofficially used 465. Alternatively, we can try to register a new port, but what are the chances of people actually migrating to the new default for secure submission? 2.2. Mail User Agent Requirements This section describes requirements on Mail User Agents (MUAs) using IMAP, POP, and/or Submission protocols. Note: Requirements pertaining to use of Submission servers are also applicable to use of SMTP servers (whether on port 25 or on another port as advertised by a SRV record with _smtp._tcp or _smtps._tcp label) for mail submission. This note seems a bit out of place, as you already mentioned elsewhere that MTA-to-MTA SMTP is out of scope for this document. Plus you are sort of trying to register smtps here, but you really don't. 2.2.8. Requirements for MUA use of TLS MUAs MUST use the procedure defined in [RFC6125] to determine whether a server's TLS certificate contains an identifier which matches the DNS name to which the MUA is attempting to connect, and MUST abort the TLS session if the server's certificate does not present an identifier that matches one of the MUA's predetermined reference identifiers for that server. It is important to avoid using DNS names obtained from SRV records (rather than from explicit user configuration) as reference identifiers when comparing with presented identifiers in TLS server certificates, unless those SRV records were signed with DNSSEC and the signatures were verified by the MUA. Note in Draft: [I-D.melnikov-email-tls-certs] describes a profile of [RFC6125] for use in MUA checking of presented identifiers in TLS server certificates. Not surprisingly, I think that you should delete the second quoted paragraph (my draft already includes it) and update the first paragraph to reference [I-D.melnikov-email-tls-certs]. This would also make [I-D.melnikov-email-tls-certs] normative. The problem with your first paragraph is that just referencing RFC 6125 is not enough to get interoperability, because any use of RFC 6125 needs to describe use or non use of several parameters, like SRV-ID, CN-ID, etc. 2.2.12. Use of DANE by MUAs o TLSA record exists and has a valid DNSSEC signature, and the public key specified in a TLSA record matches the public key in the X.509 certificate presented by the server. However, the server certificate is not signed by a trusted certificate authority, I think this might not be relevant, depending on the TLSA record type used. nor has the MUA been explicitly configured ("pinned") to accept that particular certificate. In this case the connection MUST gracefully terminate the session with the server without attempting to authenticate or request services. Isn't this the case for asking the user to pin the certificate? 3.3. TLS Server Certificate Requirements MSPs MUST maintain valid server certificates for all servers. Those server certificates MUST present DNS-IDs and SRV-IDs conforming to [RFC6125] and which will be recognized by MUAs meeting the requirements of this memo. In addition, those server certificates MAY provide other DNS-IDs, SRV-IDs, or CN-IDs needed for compatibility with legacy MUAs. Again, I think this should reference [I-D.melnikov-email-tls-certs]. [RFC4409] Gellens, R. and J. Klensin, "Message Submission for Mail", RFC 4409, April 2006. This was obsoleted by RFC 6409, so there is no need to reference both Normatively.
- [ietf-smtp] Request for discussion of Mandatory S… Wei Chuang
- Re: [ietf-smtp] Request for discussion of Mandato… Timo Sirainen
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] Request for discussion of Mandato… Martijn Grooten
- Re: [ietf-smtp] Request for discussion of Mandato… John C Klensin
- Re: [ietf-smtp] Request for discussion of Mandato… SM
- Re: [ietf-smtp] Request for discussion of Mandato… Paul Smith
- Re: [ietf-smtp] Request for discussion of Mandato… Alessandro Vesely
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] Request for discussion of Mandato… Timo Sirainen
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] Request for discussion of Mandato… John Levine
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] Request for discussion of Mandato… MH Michael Hammer (5304)
- Re: [ietf-smtp] Request for discussion of Mandato… Martijn Grooten
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] Request for discussion of Mandato… John C Klensin
- Re: [ietf-smtp] Request for discussion of Mandato… John C Klensin
- Re: [ietf-smtp] DKIM encryption, was Request for … John Levine
- Re: [ietf-smtp] Request for discussion of Mandato… John C Klensin
- Re: [ietf-smtp] DKIM encryption, was Request for … Carl S. Gutekunst
- Re: [ietf-smtp] DKIM encryption, was Request for … John R Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … John C Klensin
- Re: [ietf-smtp] Request for discussion of Mandato… Brandon Long
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] Request for discussion of Mandato… Arnt Gulbrandsen
- Re: [ietf-smtp] DKIM encryption, was Request for … John R Levine
- Re: [ietf-smtp] Request for discussion of Mandato… John Levine
- Re: [ietf-smtp] Request for discussion of Mandato… Timo Sirainen
- Re: [ietf-smtp] DKIM encryption, was Request for … John C Klensin
- Re: [ietf-smtp] DKIM encryption, was Request for … Richard Clayton
- Re: [ietf-smtp] DKIM encryption, was Request for … John R Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … Robert A. Rosenberg
- Re: [ietf-smtp] DKIM encryption, was Request for … Russ Allbery
- Re: [ietf-smtp] DKIM encryption, was Request for … Alessandro Vesely
- Re: [ietf-smtp] Request for discussion of Mandato… Arnt Gulbrandsen
- Re: [ietf-smtp] DKIM encryption, was Request for … John Levine
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] DKIM encryption, was Request for … Martijn Grooten
- Re: [ietf-smtp] DKIM encryption, was Request for … Murray S. Kucherawy
- Re: [ietf-smtp] DKIM encryption, was Request for … Rolf E. Sonneveld
- Re: [ietf-smtp] DKIM encryption, was Request for … Steve Atkins
- Re: [ietf-smtp] DKIM encryption, was Request for … Dave Crocker
- Re: [ietf-smtp] DKIM encryption, was Request for … John Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … Martijn Grooten
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] Request for discussion of Mandato… Wei Chuang
- Re: [ietf-smtp] DKIM encryption, was Request for … Richard Clayton
- Re: [ietf-smtp] Request for discussion of Mandato… SM
- Re: [ietf-smtp] DKIM encryption, was Request for … Ned Freed
- Re: [ietf-smtp] DKIM encryption, was Request for … SM
- Re: [ietf-smtp] DKIM encryption, was Request for … Rolf E. Sonneveld
- Re: [ietf-smtp] DKIM encryption, was Request for … John Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … Rolf E. Sonneveld
- Re: [ietf-smtp] DKIM encryption, was Request for … Ned Freed
- Re: [ietf-smtp] DKIM encryption, was Request for … John C Klensin
- Re: [ietf-smtp] DKIM encryption, was Request for … Wei Chuang
- Re: [ietf-smtp] DKIM encryption, was Request for … John Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … Wei Chuang
- Re: [ietf-smtp] DKIM encryption, was Request for … Russ Allbery
- Re: [ietf-smtp] DKIM encryption, was Request for … Ned Freed
- Re: [ietf-smtp] DKIM encryption, was Request for … Ned Freed
- Re: [ietf-smtp] DKIM encryption, was Request for … John R Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … Ned Freed
- Re: [ietf-smtp] DKIM encryption, was Request for … Ned Freed
- Re: [ietf-smtp] DKIM encryption, was Request for … John R Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … John R Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … John R Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … Ned Freed
- Re: [ietf-smtp] DKIM encryption, was Request for … Dave Crocker
- Re: [ietf-smtp] DKIM encryption, was Request for … John Levine
- Re: [ietf-smtp] DKIM encryption, was Request for … Ned Freed
- Re: [ietf-smtp] DKIM encryption, was Request for … Wei Chuang
- Re: [ietf-smtp] DKIM encryption, was Request for … Martijn Grooten
- Re: [ietf-smtp] DKIM encryption, was Request for … Steve Atkins
- Re: [ietf-smtp] DKIM encryption, was Request for … Martijn Grooten
- Re: [ietf-smtp] DKIM encryption, was Request for … James Cloos
- Re: [ietf-smtp] DKIM encryption, was Request for … Wei Chuang
- [ietf-smtp] Two recent Internet-Drafts about usin… Keith Moore
- Re: [ietf-smtp] Two recent Internet-Drafts about … Paul Smith
- Re: [ietf-smtp] Two recent Internet-Drafts about … Stephan Bosch
- Re: [ietf-smtp] Two recent Internet-Drafts about … Rolf E. Sonneveld
- Re: [ietf-smtp] Two recent Internet-Drafts about … Wei Chuang
- Re: [ietf-smtp] Two recent Internet-Drafts about … Keith Moore
- Re: [ietf-smtp] Two recent Internet-Drafts about … Ned Freed
- Re: [ietf-smtp] Two recent Internet-Drafts about … John Levine
- Re: [ietf-smtp] Two recent Internet-Drafts about … John Levine
- Re: [ietf-smtp] Two recent Internet-Drafts about … Wei Chuang
- Re: [ietf-smtp] Two recent Internet-Drafts about … Brandon Long
- Re: [ietf-smtp] Two recent Internet-Drafts about … Wei Chuang
- Re: [ietf-smtp] Two recent Internet-Drafts about … Wei Chuang
- Re: [ietf-smtp] Two recent Internet-Drafts about … Ned Freed
- Re: [ietf-smtp] Two recent Internet-Drafts about … Dave Crocker
- Re: [ietf-smtp] Two recent Internet-Drafts about … Paul Smith
- [ietf-smtp] Review of draft-moore-email-tls-00.txt Alexey Melnikov
- Re: [ietf-smtp] Review of draft-moore-email-tls-0… Keith Moore