commandlinefu.com is the place to record those command-line gems that you return to again and again.
You can sign-in using OpenID credentials, or register a traditional username and password.
Subscribe to the feed for:
Allows you to connect to an SMTP server over TLS, which is useful for debugging SMTP sessions. (Much like telnet to 25/tcp). Once connected you can manually issue SMTP commands in the clear (e.g. EHLO)