ipfw2 & natd & stateful

[Tommy Forrest]

Maybe impossible in FreeBSD - cause our Checkpoint firewalls do not have
this problem.

On Mon, 19 May 2003, Craig Reyenga wrote:

> I'm pretty sure that NATD + stateful is impossible because in order to have
>
> [unregistered ip] <-> [internet ip]
>
> you need:
> [unregistered ip] <-> [gateway]
>     [natd operates here]
> [gateway] <-> [internet ip]
>
> but ipfw doesnt do this, so your connections end up not working, because the
> stateful rules don't make the second scenario, they make the first.
>
> (I'd love to be proven wrong, as I have a similar setup.)
>
> Hope this helps,
>
> -Craig
>
>
>
> ----- Original Message -----
> From: "Asenchi" <asenchi at asenchi.com>
> To: <freebsd-questions at freebsd.org>
> Sent: Monday, May 19, 2003 8:40 AM
> Subject: ipfw2 & natd & stateful
>
>
> > Hello Everyone.
> >
> > I have a bit of a problem. I want to switch my company's firewall to IPFW2
> > but I can't seem to get the ruleset to work. After sidelining the notion,
> I
> > am ready to attack this again. I have had many problems with it. (You can
> > see a discussion on this issue here:
> > <http://www.freebsdforums.org/forums/showthread.php?s=&threadid=9061)
> >
> > It seems that NATD is stopping anyone on my internal network from getting
> > through to websites. I does some how reach DNS but won't go anywhere else.
> I
> > have tried multiple things...
> >
> > I use this ruleset almost verbatim on another machine that isn't running
> > NATD. Can anyone see anything here? I don't subscribe to this list with
> this
> > email address, so could you please cc me?
> >
> > Thanks in advance to anyone who can offer some light...
> >
> > ////curt////
> >
> > Here is the output of 'ipfw -d show'
> >
> > 00100 0 0 check-state
> > 00200 4 164 deny log logamount 1000 ip from any to any established
> > 00300 28 1789 divert 8668 ip from any to any via vr0
> > 00400 0 0 deny log logamount 10 ip from 192.168.0.0/24 to any via vr0
> > 00500 38 3897 allow { tcp or udp } from me to { 198.109.160.2 or dst-ip
> > 198.109.160.3 or dst-ip d.n.s.1 or dst-ip d.n.s.2 } dst-port 53 out xmit
> vr0
> > keep-state
> > 00600 306 31838 allow tcp from { o.u.t.2/29 or o.u.t.1 or 2.1.0.0/16 or
> > 1.1.0.0/16 } to me dst-port 22 setup in recv vr0 keep-state
> > 00700 22 992 allow tcp from me to any setup via vr0 keep-state
> > 00800 2 120 deny log logamount 1000 { tcp or udp } from any to me
> > 01000 7 336 allow log logamount 1000 tcp from i.n.t.r/24 to any dst-port
> 80
> > 01100 0 0 allow tcp from 192.168.0.0/24 to any setup keep-state
> > 01200 66 4168 allow { tcp or udp } from 192.168.0.0/24 to { d.n.s.3 or
> > dst-ip d.n.s.4 or dst-ip d.n.s.1 or dst-ip d.n.s.2 } dst-port 53
> keep-state
> > 01300 0 0 allow tcp from any to 192.168.0.0/24{3,10,11,12,21,110} dst-port
> > 6501-6504 setup in recv vr0 keep-state
> > 01500 0 0 deny icmp from any to me icmptypes 8
> > 01600 131 5560 allow icmp from any to any
> > 01800 3 234 deny { tcp or udp } from any to any dst-port 137,138,520
> > 01900 4 304 deny log logamount 1000 ip from any to any
> > 65535 0 0 deny ip from any to any
> >
> > ## Dynamic rules (28):
> > 01200 3 192 (9s) STATE udp 192.168.0.64 1072 <-> d.n.s.3 53
> > 01200 5 320 (9s) STATE udp 192.168.0.64 1072 <-> d.n.s.2 53
> > 00600 305 31778 (300s) STATE tcp m.y.i.p 3020 <-> o.u.t.1 22
> >
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>
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