Hi All - I have ZCS 6.0 on Ubuntu. All email is filtered through a SPAM server that is hosted at ExchangeDefender. We have the proper certifcates installed (as well as ExchangeDefender) for TLS. I looked in the email headers and outbound email is TLS encrypted. However, inbound email is just basic SMTP (not even ESMTP). All proper ports are open.

I also noticed that internally if I run the following command, TLS looks ok.

telnet 'inside IP' 25
220 host.domain.com ESMTP Postfix
starttls
220 2.0.0 Ready to start TLS

But... If I run the same command from the outside (w/ outside IP):
telnet 'outside IP' 25
220 ********************************
starttls
502 5.5.2 Error: command not recognized


If I run this command from the outside it looks ok.
telnet 'outside IP' 465
220 host.domain.com ESMTP Postfix
starttls
220 2.0.0 Ready to start TLS


Any ideas?? Any help is greatly appreciated.
Thanks.