What happens when you ask Gmail’s SMTP server for help?

calendar Nov 23, 2008 gmail rfc smtp

Transcript of a session with Gmail's SMTP server. Items in italics are my entries.

bowser:~> telnet gsmtp183.google.com 25
Trying 64.233.183.27...
Connected to gsmtp183.google.com.
Escape character is '^]'.
220 mx.google.com ESMTP h6si2778348nfh.21
HELO localhost
250 mx.google.com at your service
HELP
214 2.0.0 http://www.google.com/search?btnI&q=RFC+2821 h6si2778348nfh.21
QUIT
221 2.0.0 closing connection h6si2778348nfh.21
Connection closed by foreign host.
Traditionally, the HELP command in the SMTP protocol would generate a list of commands supported by the mail server. Most mail servers today simply ignore the command. Google, naturally, points the client to the appropriate RFC—retrieved with nothing less than a Google I'm Feeling Lucky search...