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Originally published at Internet.comFirewalls are usually seen as a requirement if you are going to attach your network to other networks, especially the Internet. Unfortunately, some network administrators and managers do not understand the strengths a firewall can offer, resulting in poor product choice, deployment, configuration and management. Like any security technology, firewalls are only effective if the implementation is done properly and there is proper maintenance and response to security events.
Additionally, with the proper deployment of firewalls other security strategies are often much easier to integrate, such as VPNs and IDS systems. So what makes firewalls good, and what can you do to ensure they are used properly?
Perimeter Defense
One of firewalls' weaknesses is also one of their strengths. Firewalls are typically deployed as a perimeter defense, usually intersecting network links that connect your network to others. If the firewall is properly deployed on all paths into your network, you can control what enters and leaves your network.
Of course, as with any form of perimeter defense, if an attack is launched from inside, firewalls are not too effective. However, this deployment on your network perimeter allows you to prevent certain kinds of data from entering your network, such as scans and probes, or even malicious attacks against services you run...
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