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Date:      Sat, 19 Aug 2000 22:32:41 -0700 (PDT)
From:      Todd Backman <todd@flyingcroc.net>
To:        freebsd-security@freebsd.org
Subject:   Routing firewall w/ipfw questions
Message-ID:  <Pine.BSF.4.21.0008192142110.27579-100000@security1.noc.flyingcroc.net>

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Greetings!

I am setting up a firewall to protect a class c network and am having
difficulty with routing. Here is the scenario (ips changed to protect the
guilty):

Firewall box running 4.0 stable with plenty of horsepower and 2 nics.

outside interface is set to xxx.xxx.xxx.83 in a /29 netmask .248

inside interface is going to be set to xxx.xxx.xxx.1 in a /24 netmask .0

gateway of inside net is currently on a virtual interface on a router with
the IP of xxx.xxx.xxx.1 

Problem:
When testing the firewall today I had one of the neteng guys shut the virt
int on the router, re-route the traffic destined for the inside net to the
outside interface of the firewall and brought up the xxx.xxx.xxx.1 on the
inside interface. After that was accomplished I had someone test
connectivity outbound from within the /24 that I am attempting to protect
and all was fine. However, inbound traffic to the outside interface and/or
the internal /24 was not passing. I could not even traceroute to the
outside interface at all. At that time I figured that I had not spent
enough time on my rules and went ahead and set ipfw to pass ip from any to
any. Still no luck. 

Question:
Is my reasoning flawed in regards to the routing portion of this setup? I
made sure that ipforwarding was enabled as well. (please let me know if
you need more info to assist with this problem) I am not a routing whiz so
I'll need the big thump with the clue bat for sure...

Thanks for any help you might provide. Upon successful completion of this
project I will document all *correct* procedures and post as I have not
found any documentation on setting ipfw up for protecting an internal /24 
with a different subnet on the outside interface.

- Todd

BTW...has anyone discussed some sort of document pool for various projects
that freebsd users implement? There are many of us out here that have done
some pretty cool stuff and if we all dump our docs somewhere with a search
tool on the front end...? I do understand that many of our documentation
methods (or lack there of) are diff but I think that the variety of
directions and slightly diff circumstances regarding the implementations
are a plus. I certainly would not mind sifting through others' docs
looking for the right match to any of my hair-pulling projects. Just my
.02. And, yes, I am willing to donate time/resources (and my docs) to the
project. 



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