On Thursday 05 May 2016 15:34:48 Alexander Dalloz wrote: > Connect with: > > openssl s_client -connect <your server IP address>:143 -starttls imap > > Then issue IMAP commands: > > 01 CAPABILITY > 02 LOGIN user password > 03 LOGOUT > > That should be successful and you should have seen the configured AUTH > mechanisms. Now try without transport layer security: > > telnet <your server IP address> 143 > > 01 LOGIN user password > > That should be forbidden because of LOGINDISABLED. > > Regards > > Alexander Thanks for this Alexander. I tried this from inside my LAN and both the openssl and the telnet sessions worked. I then tried it from outside my LAN and the openssl session worked while the telnet session failed. Exactly what I wanted. That does beg the question as to why Thunderbird failed.