On Thu, 2022-03-17 at 15:05 +0800, Jeremy Ardley wrote: > I've been using Thunderbird for years now but made some minor tweaks as > I'm setting up an imap proxy for remote access to my > debian/dovecot/postfix server. > > The issue is I changed the account settings in thunderbird to use > STARTTLS and port 993. It now doesn't work. I see a connection in > wireshark, but then nothing happens and dovecot logs no attempt to > authenticate and it just times out. > > I also installed claws email (which I'm using for this email) It has > the same settings and works flawlessly from the same client machine I > use for thunderbird. I conclude there are no routing issues or firewall > issues.
Isn't port 993 for IMAP over TLS? And STARTTLS is a protocol for upgrading a non-TLS connection to TLS (as you would use on IMAP port 143) Perhaps you should not be using STARTTLS but just connecting initially as TLS. My MUA (Evolution) has three options for connections... - No Encryption. - STARTTLS after connection. - TLS on dedicated port. I use the latter to connect to my Dovecot server, on port 993. -- Tixy