Zugschlusbeobachtungen

Description: SMTP command-line test tool
 swaks (Swiss Army Knife SMTP) is a command-line tool written in Perl
 for testing SMTP setups; it supports STARTTLS and SMTP AUTH (PLAIN,
 LOGIN, CRAM-MD5, SPA, and DIGEST-MD5). swaks allows to stop the SMTP
 dialog at any stage, e.g to check RCPT TO: without actually sending a
 mail.
 .
 If you are spending too much time iterating "telnet foo.example 25"
 swaks is for you.

A very important tool which makes debugging e-mail a breeze. A must for every mail admin.