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Date:      Sat, 29 Dec 2001 01:58:17 -0800 (PST)
From:      Julian Elischer <julian@elischer.org>
To:        cjclark@alum.mit.edu
Cc:        Henry Su <henrysu@nttmcl.com>, freebsd-net@FreeBSD.ORG
Subject:   Re: Why is my ipfw(8) ``fwd'' rule to redirect a service to another machine not working?
Message-ID:  <Pine.BSF.4.21.0112290156100.97641-100000@InterJet.elischer.org>
In-Reply-To: <20011228184516.B93411@blossom.cjclark.org>

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On Fri, 28 Dec 2001, Crist J . Clark wrote:

> On Fri, Dec 28, 2001 at 01:31:07PM -0800, Julian Elischer wrote:
> > You need to 
> > correct the FAQ..
> > 
> > "The correct way to ensure that this does not happen is to also add
> > a 'fwd' rule on the destination rule, forwarding the packet 
> > to localhost. This will override the destination machine's tendancy
> > to throw the forwarded packet back"
> 
> I'm having a hard time parsing that.

if you send a packet somewhere it is not supposed to go, it will try
discard it or forward it, UNLESS it has an ipfw fwd rule that makes it 
forward it to a local port. So you need a rule at the interception machine
and a rule at the destination machine.




> 
> > Also, in versions of FreeBSD before 4.6,
> 
> 4.6?


yes, it will miss 4.5

> 
> > packets matched while INCOMING
> > could only be forwarded to the local host.
> 
> Which is what I thought the original poster was doing?
> 
> > Outgoing packets
> > could be forwarded to an adjoining host.
> > This was fixed while 4.5 was cooking and appeared in releases after that.
> 
> So will this be in 4.5?

No
> 
> > The port number is only used for forwarding to the local host.
> 
> Which is what the original poster was doing?
> -- 
> "It's always funny until someone gets hurt. Then it's hilarious."
> 
> Crist J. Clark                     |     cjclark@alum.mit.edu
>                                    |     cjclark@jhu.edu
> http://people.freebsd.org/~cjc/    |     cjc@freebsd.org
> 


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