An SMTP Protocol Hacker. Vrfy.pl uses the vrfy command to verify users/mail accounts on a network by using a list of common system names like root, admin, etc…

Basically it bruteforces SMTP server to find usernames from a list of possible names.

We used the following command vrfy.pl -h smtp.digg.com -l names.txt

That’s how you the do it. :)

pavs