I have a FC server running postfix as a backup mx relay server for our exchange domain. Question is, i see many cases where spammers look for a server such as this to spam through. Is there a way to discourage spammers from trying to spam our server? I used teh HowTo for MX backup to set this up, and it works.
All you have to do is make sure that your server is no open relay. http://www.spamhelp.org/shopenrelay/
