On Wed, 13 Mar 2024, Gellner, Oliver via mailop wrote:
Sending MTAs which do not support modern crypto on the other hand are going to fall back to a unencrypted connection as soon as you disable older cipher suites. This allows any, even passive MITM to read and/or modify the messages. A claim that TLS 1.0 or 1.1 would be equally unsafe as completely unencrypted communications is a cliche and not based on facts.
Correct me if I'm wrong, but a client connecting to an SMTP-server and sees STARTTLS does just that, starts TLS. When the negotiation fails because there's no common ciphers (client at max TSLv1.1, server at min TLSv1.2) the connections fails completely. The client is unable to undo the STARTTLS.
Are there SMTP-"clients" that actually are able to back down from STARTTLS and continue unencrypted?
I have seen a few old linux boxen that tried to send e-mail and it would have been possible to allow incoming with "DEFAULT@SECLEVEL" but meh. Most have upgraded their systems.
Good point about decade old printers though. -- Harald Hannelius | har...@iki.fi | +358505941020 _______________________________________________ mailop mailing list mailop@mailop.org https://list.mailop.org/listinfo/mailop
