stateful firewall

Mihai Marie mmarie at
Thu Feb 26 00:13:52 PST 2004


I want to setup a firewall (on my LAN's gateway) so that the only
traffic that pass through is the one initiated from my local network (we
have public IP's).

My firewall looks like this

ipfw add check-state
ipfw add deny tcp from any to any established
ipfw add allow tcp from $my_lan to any setup keep-state

The problems appear when I want to make some ftp traffic with a server
that is outside (or any other traffic that tries to open a new separated
connection in relation with the one initiated from our LAN).

With iptables (in redhat) you can do:

iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT

but I don't know how can I do something like this using ipfw or another
firewall on FreeBSD.

Any help would be appreciated,

Mihai Marie

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