Re: [Shutup] [ietf-smtp] Fwd: New Version Notification for draft-fenton-smtp-require-tls-00.txt
Jim Fenton <fenton@bluepopcorn.net> Mon, 11 January 2016 19:26 UTC
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To: John Levine <johnl@taugh.com>, ietf-smtp@ietf.org, shutup@ietf.org
References: <20160111163401.48404.qmail@ary.lan>
From: Jim Fenton <fenton@bluepopcorn.net>
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Date: Mon, 11 Jan 2016 11:25:28 -0800
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Subject: Re: [Shutup] [ietf-smtp] Fwd: New Version Notification for draft-fenton-smtp-require-tls-00.txt
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On 1/11/16 8:34 AM, John Levine wrote: >>> Only sort of. In this case, the downgrade path is obvious, you >>> ignore the TLS flag and send the message along. >> That's the opposite of the goal here. SMTP makes tries to delivery >> messages, even if that results in a downgrade in security. The goal here >> is to fail the transmission of REQUIRETLS tagged messages that can't be >> sent in accordance with the originator's security requirements. > Of course, but there's no reason for recipient MTAs to pay any > attention to the tag if they don't want to. There is no penalty to > them for doing so. With EAI there's at least the penalty of messages > getting smashed. Misbehavior by MTAs is outside the scope of the threat model for SMTP TLS. I have already described how such behavior could be detected; the erosion of trust resulting from that is likely to be harmful to the mail provider's business model. -Jim