i'm a newbie!
i care about packet filter in FreeBSD.
how i have document about that?
please help me!

Welllll, here it is...!

http://www.obfuscation.org/ipf/

Cheers

could you help me...
how Packet filter know a packet is coded by ssh?
how packet had been deal by packet filter?
thanks!

Hello there...

We're both non-anglophones I presume, so this ought to be fun ( finding our way around the typos, that is... ).

If I understood your question correctly:
Packet filters know nothing about protocols like SSH, HTTP, FTP and the like. Packet filters only worry about from and to which ip and port a packet is destined.
Protocols, however, adhere to a loose specification in terms of what ports they use to comunicate; SSH listens on port tcp/22 for incoming connections.
But if you're not aware of this already, then you need to read a bit about the subject first or else you'll might end up finding these forums not to be of much help...

Cheers

hiii. thanhks !
You know, i care about protocol SSH, VPN...
Packet filter know nothing about them, but how pakcet filter will realize them , and forwarding application level!
example:VPN is coded AH, ID in option IP 51, ESP 50...
I care about traffic special, and packet filter will resolve them!
thanks....help me!

Hi again...

I'm afraid I have zero knowledge about VPN setup and operation...