I run a server with DNS (bind9), mail (postfix), and web (apache) services. I used the ISPConfig "Perfect Server" tutorials and installed ISPConfig 3. Everything works fine, for the most part. However, because I send and receive mail using Gmail, my emails say "On behalf of" my gmail address. The email addresses I use with Gmail are forwarded using ISPConfig 3's forwarding feature. I'd like to set up a way to use my server as the SMTP server for the mail that I store on Gmail. However, I'm having some trouble getting the SMTPAuth to work properly. When I try to test an account with a known password by telneting to port 587 on my server, I get the following exchange: Connected to mydomain.com. Escape character is '^]'. 220 mail.mydomain.com ESMTP Postfix (Ubuntu) ehlo my.host 250-mail.mydomain.com 250-PIPELINING 250-SIZE 20480000 250-VRFY 250-ETRN 250-STARTTLS 250-ENHANCEDSTATUSCODES 250-8BITMIME 250 DSN STARTTLS 220 2.0.0 Ready to start TLS PASSWORD GOES HERE In my mail log, I get: warning: TLS library problem: 25352:error:140760FC:SSL routines:SSL23_GET_CLIENT_HELLO:unknown protocol:s23_srvr.c:578: Any help would be greatly appreciated.