"Is it better to run your company’s firewall or IDS using an open source tool,
or is it better to buy something off the shelf? Let’s step through some of the
most common arguments used by each side of the open source security debate and
see how they do or do not stand up in the light of practical
reality."
Article Link: http://www.linuxinsider.com/story/b7hsTTW4HhJARZ/The-Truth-About-Open-Source-Security.xhtml
