Attackers commonly look for remote vulnerabilities in order to compromise the resources on your network. BackTrack Linux, a security-testing distribution, can help you inspect your network and servers for remote security weaknesses and potential vulnerabilities.
BackTrack, which is based on Ubuntu, bundles all the tools necessary for penetration testing and security audits. You don’t really have to run BackTrack to use the tools it provides, but booting up a BackTrack live CD lets you get started in no time.