Someone told me about COMODO Firewall the other day, and said it was free, lightweight, fast, and simple. Well, I tried it, and here’s what I found:

If you want application-based control, this program is great.

If you want component-based control, this program is even better.

The above 2 work well because this software has the option of using a “safe list” of components and applications from COMODO’s servers somewhere, which can seriously simplify things for new users, so you don’t get bombarded out of the gate with access requests from the program.

If you just want simple, rule-based, network filter level control, this program is FUCKING PERFECT. It’s basically like iptables for Windows. Here’s how I set mine up:

1. Turn off application and component control, and application behavior analysis
2. Delete all the rules in the network monitor component except the last one (the default drop) and the incoming ICMP ones if you actually care if hosts are dead (for most people, this will only speed up error notification, since the OS will timeout packets at some point anyway).
3. Add your own rules above the default drop for allows
4. Finally, add at the very top an allow all outgoing IP rule, so your outgoing traffic is allowed
5. If you use windows on a windows network, you’ll need to allow incoming 135/udp or network names won’t resolve when the machines tries to resolve by using broadcasts. You can ignore this if you’re a DNS/WINS only setup.

That’s all there is to it. The program is relatively gentle on system resources; it uses about 14 MB of RAM, and doesn’t slow down the system with bloat the way ZoneAlarm did. I also like how this program makes no assumptions; ZoneAlarm implicitly allows certain types of traffic (like the aforementioned 135/udp) without telling you, because it just *assumes* it’s needed for windows, and thereby necessary.

In any event, I’d recommend this firewall if you are a Linux user with an iptables addiction; otherwise, there’s nothing special about this aside from the fact that it’s free.

To get the program for free, you give COMODO your email address (hooray for spamgourmet) and they send you an activation code that’s good for life.