Roundcube + Dovecot: SSL errors when trying to log in

The different meaning of tls:// and ssl:// in $config['default_host'] is unfortunately not documented.

• tls:// means usage of STARTTLS, thus usually port 143

• ssl:// means usage of TLS, thus usually port 993

• The same is valid for $config['smtp_server'] and ports 25 and 587 for tls://, ports 465 for ssl://.

Can't give any source for this information, as I (and some others) got it empirically.

And for the verify_peer issue, first look at the cert that is served. E.g. using this command from the connecting machine:

echo | openssl s_client -connect mail.fizeau.net:143 -starttls imap -showcerts 2>&1 | openssl x509 -noout -text | egrep 'Subject: |DNS:'

This will show you the domains, the cert was issued for.