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Date:      Wed, 11 Apr 2001 16:59:23 +0100
From:      Rasputin <rara.rasputin@virgin.net>
To:        freebsd-security@freebsd.org
Cc:        lowell@world.std.com
Subject:   Re: Interaction between ipfw, IPSEC and natd
Message-ID:  <20010411165923.A70350@dogma.freebsd-uk.eu.org>
In-Reply-To: <44bsq331ck.fsf@lowellg.ne.mediaone.net>; from lowell@world.std.com on Wed, Apr 11, 2001 at 11:25:31AM -0400
References:  <20010410181407.A1011@linnet.org> <20010411100036.B63302@dogma.freebsd-uk.eu.org> <44bsq331ck.fsf@lowellg.ne.mediaone.net>

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* Lowell Gilbert <lowell@world.std.com> [010411 16:29]:
> rara.rasputin@virgin.net (Rasputin) writes:

> > Does anybody know if ipfilter has similar problems with IPSec?

> Some forms of IPSEC have fundamental problems with packet rewriting,
> which means that NAT is extremely hard to use in an IPSEC environment.
> Notably, end-to-end IPSEC modes are broken, although router-based
> tunnels can be a problem depending on whether the NAT rewriting occurs
> before or after the IPSEC headers are applied.

Sorry, should have made it clearer. I'm not running a VPN or anything,
I just need to secure a wireless network. So I need transport mode IPSec
on top of IPv4 from iBook clients to the BSD gateway/firewall.
NAT would take place *after* the packets reach the gateway, on the outbound interface.

Cheers anyway, I'm an ipf fan so I'll grit my teeth through that.
 
> Even without NAT, though, firewalls are a little tricky to configure
> for IPSEC packets.  This is because the firewall can't see the
> protocol ports (or even the protocol, for that matter) in the packet,
> so you have to make pass/drop decisions for IPSEC packets without that
> information. 

> Everybody is ignorant, only on different subjects.
> 		-- Will Rogers

Amen to that :)
-- 
"No problem is so formidable that you can't just walk away from it."
Rasputin
Jack of All Trades :: Master of Nuns

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