DNATing packets sent to the NATing box

[horape@tinuviel.compendium.com.ar]

I've a system that at its core has an UDP proxy that's the performance
bottleneck. I wanted to use the DNAT kernel facilities to replace my
code with the very tuned one on netfilter.

I'm adding a rule that says something like this:

/sbin/iptables -t nat -A PREROUTING -d myip -p udp -m udp --dport 5000 -j DNAT
		--to-destination otherip:18918

but the rule never see the packets (they never got to the chain)

I assume that it's because I've a socket listening on udp:5000, and it seems
reasonable what's happening... I'd like to add a PREPREROUTING chain that
is processed before deciding if the packet is for a local socket, can somebody
give me a hint on where to look for it?

Saludos,
					HoraPe
---
Horacio J. Peña
horape@compendium.com.ar
horape@uninet.edu