Re: DNATing packets sent to the NATing box

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On December 14, 2003 12:35 pm, Jeffrey Laramie wrote:
> On Sunday 14 December 2003 12:16, Antony Stone wrote:
> > On Sunday 14 December 2003 4:55 pm, Jeffrey Laramie wrote:
> > > On Sunday 14 December 2003 11:04, horape@xxxxxxxxxxxxxxxxxxxxxxxxxx 
wrote:
> > > > The proxy has a udp socket bound to port 5000, and another udp socket
> > > > bound to some other port, it reads from the first socket and does a
> > > > sendto using the other socket (poll + read + write, no more)
> > >
> > > It looks like the proxy is grabbing the packets first and then dropping
> > > them directly onto the INPUT chain. Try disabling the proxy and release
> > > the bound ports then try it again. Once the packets reach PREROUTING
> > > you can DNAT them to another port.
> >
> > I could ubnderstand the proxy code managing to grab the packet off the
> > wire before netfilter (PREROUTING) sees it, but I don't see how it would
> > then get seen by the INPUT chain - as far as I know, it's not possible
> > for a packet to reach netfilter's INPUT chain without first going through
> > the PREROUTING chain.   If a packet bypasses one of these, it will bypass
> > both.
>
> Well that's what I thought but I can't explain his results any other way.
> What are we missing here?
>

	My question exactly ... 
	a silly question is :
	what if anything is in /proc/net/ip_conntrack for these connections?

	Alistair Tonner

> Jeff


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