I was just wondering, is Netfilter as good as Cisco's PIX and Checkpoint's Firewall-1, if not better?

Also I'm wondering say if I have a dmz and allow people to come into a server on port 80, will netfilter inspect the packet on all 7 layers of the OSI model and make sure that it is actually a http packet and following the rules and protocol specifications of http? Sorta like checkpoints INSPECT module.

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I have not failed 10,000 times, I have sucessfully found 10,000 ways that won't work." -- Thomas A. Edison