On Mon, Oct 17, 2022 at 03:00:11PM +0200, Marek Podmaka wrote: > On Mon, 17 Oct 2022 at 14:57, Wietse Venema <wie...@porcupine.org> wrote: > > > > For Postfix submission and smtps we prefer > > > > tls_ssl_options = NO_RENEGOTIATION, NO_TICKET > > > > Instead of forcing hostname/cert micmatches. > > Yes, I am already using NO_TICKET and it is also recommended by the > linked article. However it is still interesting that using different > cert does not trigger the bug.
If possible, please ask the other user whether the alternative certificate again sports a mismatched hostname. It is somewhat plausible that the Microsoft bug doesn't fire when certificate chain validation bails out early due to the mismatched hostname. -- Viktor.