How does the popular Nmap scanner identify holes in network security? In this article, we examine some Nmap analysis techniques.

Realtime virus scanning at the file server is an elegant and efficient option for protecting Windows clients. We’ll show you some tools and techniques for realtime scanning with Samba.

Caching proxies remember web pages and serve them up locally, saving both money and time. The most intelligent members of this family also remove dangerous content and provide transparent bridging.

We’ll show you how to build your own Netfilter extension with this example of a musical firewall.

The Apache ModSecurity module provides extra protection for your web server. We'll show you why this optional application firewall is quickly becoming a favorite of webmasters and security experts.

When ports on a host start opening and closing like window shutters in a gale, it’s time for admins to pay attention.

After penetrating a remote system, intruders might think they are home and dry, but AppArmor spoils the fun, locking the miscreants in a virtual cage.