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Software is the key to protecting your systems and asserting your right to control what can access your computer, e-mail box, network, etc.

SMTP Server

  • exim - The mail server software of choice for the SOSDG & AHBL.  Can support many configurations and complex access control lists.

Spam Filtering

  • SpamAssassin - Perhaps the most popular spam filtering software to integrate with UNIX mail systems, scores messages by content, allowing administrators and users extremely fine-grained control over their incoming e-mail.
  • SpamAssassin/SOSDG Filters - Our custom filters we use on our own systems.  Compiled from our own traps, these filters are very safe to use and updated often.


  • Firewall/SOSDG - Our premiere firewall for Linux machines using iptables/netfilter.  Easy to use, easy to setup, and highly customizable.