Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Chris Newman
On 27 Oct 2017, at 11:34, Eric Rescorla wrote: On Fri, Oct 27, 2017 at 11:03 AM, Chris Newman wrote: On 26 Oct 2017, at 19:56, Keith Moore wrote: On 10/26/2017 07:18 PM, Chris Newman wrote: Line 304 preference to services supporting STARTTLS (if offered). (See also Section

Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Eric Rescorla
Yeah, this doesn't seem like an actually secure set of practices, which is why we don't do it for HTTPS even when there are CNAMEs. -Ekr On Fri, Oct 27, 2017 at 12:20 PM, Viktor Dukhovni wrote: > > > > On Oct 27, 2017, at 2:34 PM, Eric Rescorla wrote: > > > > So to be clear, what you are sayi

Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Viktor Dukhovni
> On Oct 27, 2017, at 2:34 PM, Eric Rescorla wrote: > > So to be clear, what you are saying is that when I enter "mail.example.com" > but it's hosted on "mailhosting.com", and that indirection is done via SRV, > that the certificate contains "mail.example.com" but the SNI contains > "mailhos

Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Eric Rescorla
On Fri, Oct 27, 2017 at 11:03 AM, Chris Newman wrote: > On 26 Oct 2017, at 19:56, Keith Moore wrote: > >> On 10/26/2017 07:18 PM, Chris Newman wrote: >> >> Line 304 >preference to services supporting STARTTLS (if offered). (See >also Section 4.5.) > I note that 6186 i

Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Viktor Dukhovni
> On Oct 27, 2017, at 2:03 PM, Chris Newman wrote: > > I just re-read the related text a bit more carefully. Although RFC 7817 > adequately covers what subjectAltName identities mail servers need to support > in certificates, it doesn't cover what goes in SNI (although it mentions > SNI). Di

Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Chris Newman
On 26 Oct 2017, at 19:56, Keith Moore wrote: On 10/26/2017 07:18 PM, Chris Newman wrote: Line 304    preference to services supporting STARTTLS (if offered).  (See    also Section 4.5.) I note that 6186 is kind of unclear on what should go in SNI. It obviously needs to be what you ar

Re: [Uta] STS and SNI (was Re: Interaction between MTA-STS and DANE)

2017-10-27 Thread Alberto Bertogli
On Thu, Oct 26, 2017 at 09:35:34PM -0400, Viktor Dukhovni wrote: > > On Oct 26, 2017, at 9:21 PM, Jim Fenton wrote: > > > > The question I have is: Why are we matching the certificate against the > > policy rather than against the hostname, and is that done in any other > > context? Does that offe

Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Eric Rescorla
Perhaps it would be useful if Chris could walk through the example he gave in more detail. My point is that if the client is configured to connect to "pop.example.com" that has to be in the certificate, regardless of how many SRV records there are. -Ekr On Fri, Oct 27, 2017 at 7:16 AM, Keith Moo

Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Keith Moore
> On Oct 27, 2017, at 7:48 AM, Eric Rescorla wrote: > > The entire principle here is that (absent DNSSEC) TLS operates on what was > fed into the client. Could you elaborate a bit? I feel like I'm missing some context. Thanks, Keith ___ Uta mai

Re: [Uta] Eric Rescorla's Yes on draft-ietf-uta-email-deep-09: (with COMMENT)

2017-10-27 Thread Eric Rescorla
On Thu, Oct 26, 2017 at 7:56 PM, Keith Moore wrote: > On 10/26/2017 07:18 PM, Chris Newman wrote: > > Line 304 >preference to services supporting STARTTLS (if offered). (See >also Section 4.5.) > I note that 6186 is kind of unclear on what should go in SNI. It obviously > needs t

Re: [Uta] Establishing minimum TLS requirements for use with STS

2017-10-27 Thread Viktor Dukhovni
> On Oct 27, 2017, at 5:02 AM, Hanno Böck wrote: > >> Which is different from >> requiring that clients or servers reject weaker options, but given >> such a server requirement, it would not be too unreasonable for STS >> clients to in fact require at least TLS 1.2 and its MIT ciphersuites >> f

Re: [Uta] Establishing minimum TLS requirements for use with STS

2017-10-27 Thread Hanno Böck
On Wed, 25 Oct 2017 18:57:05 -0400 Viktor Dukhovni wrote: > Which is different from > requiring that clients or servers reject weaker options, but given > such a server requirement, it would not be too unreasonable for STS > clients to in fact require at least TLS 1.2 and its MIT ciphersuites > f