Providing security against email related threats has become a burden for most IT professionals in 2006. According to a recent study by Postini, spam and email viruses now make up to 80% of all emails sent out as compared to 50% in 2000. As a result, IT professionals now face a tougher challenge in providing network security for this amount of spam. IT professionals also have the disadvantage of defending against new forms of email threats such as spam zombies, directory harvest attacks, mass mailing trojans, as well as the latest email virus.

In this article, I have listed the seven most effective spam fighting tips for organizations with in-house mail servers. These seven tips are proven techniques I have used for my customers, partners and associates who wish to tighten their perimeter (network) security.

1. Firewall:

A firewall is your first line of defense against hackers, crackers, and spammers. Without a firewall, your network is a disaster waiting to happen and could give any novice hacker free reign over your network. If your organization has multiple Internet users, this tool is essential for securing your network.

2. Block Port 25:

On your firewall, allow outbound traffic on TCP port 25 for all mail servers. Block traffic on outbound TCP port 25 for all other computers and servers. On the Internet, TCP port 25 is used for email traffic through SMTP (Simple Mail Transport Protocol). Blocking this port is a good security practice and prevents mass mailing worms and spam zombies from sending mail from your users