17.03.22, 08:05 +0100, Jeremy Ardley:
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.
By default, Dovecot listens on port 993 in TLS wrappermode, i. e. the
encrypted connection has to be established before any user data can be
transmitted (nothing will be sent unecrypted).
OTOH, by telling Thunderbird to use STARTTLS you told it to try to
establish an unencrypted network connection first, and afterwards issue
the STARTTLS command over this plaintext connection to start the encryption.
This won't work. Change the connection security in TB to SSL/TLS.
--
Regards
mks
