Dictionary attacks from spammers.

[Scott Garman]

Is anyone else getting this recently? My mail server is being pounded
with a kind of spam "dictionary attack" using common first names, ie
bob at mydomain.com, sandra at mydomain.com, serg at mydomain.com, etc. It makes
a ton of noise in the logs and the host that's doing it is making
hundreds of attempts per day. 

In the past week I've had three different hosts try it, and it's
annoying enough that I've to firewall the offenders and notify the abuse
contact. 

Scott