[Tfug] iptables and spammers

[George Cohn]

Does anyone have a good iptables ruleset for blocking spammers who try 
to hit an e-mail server?

I'm using fail2ban and iptables and it works great for the ssh and 
vsftpd attacks.

What I see is a lot of spammers trying to connect to my mail server. 
They get rejected but try again and again.  I would like to add them to 
the iptables so they just get rejected immediately.

TIA

George Cohn
Tucson AZ