Re: [Tools-discuss] Phasing out TLS 1.0/1.1 on IETF services

[Viktor Dukhovni <[e-mail]>]

On Fri, Jun 24, 2022 at 05:51:48AM +0000, Eric Vyncke (evyncke) wrote:

> Based on feedback from our penetration testing contractor, and taking
> RFC8996 [1] into consideration, the IETF will begin phasing out TLS
> 1.0 and 1.1 on IETF services in the coming days,

Will this also apply to SMTP traffic to/from mail.ietf.org?

Given that most SMTP traffic is still unauthenticated STARTTLS, and that
fallback to cleartext is common after failure to deliver via TLS,
disabling TLS 1.0 and 1.1 in SMTP rarely has tangible security benefits.
It may simply result in more traffic using cleartext and delays in
message delivery.  Some sending systems don't recover from STARTTLS
failure, retrying the handshake until messages expire and bounce.

A review of the mail logs on mail.ietf.org may be appropriate to
determine whether there is still non-negligible use of TLS 1.0 with some
systems that exchange mail with ietf.org (actually deliver or receive
some mail after establishing a TLS 1.0 connection).

It is possible that ietf.org no longer exchanges mail with substantially
outdated systems that are limited to TLS 1.0, but this is worth checking.

-- 
    Viktor.