Masquerade based on skb->mark ?

[Pascal Hambourg]

Hello,

Ben Greear a écrit :
>>
>>>>> iptables -A POSTROUTING -t nat -j MASQUERADE -m mark --mark 10001
>>>>> iptables -t mangle -A PREROUTING -i eth1  -j MARK --set-mark 10001
>>>>> iptables -t mangle -A PREROUTING -i eth2  -j MARK --set-mark 10001
[...]
> If virtual router 1 is routing pkts from 1.1.1.1 to 2.2.2.2,
> and virtual router 2 is routing pkts from 1.1.1.1 to 2.2.2.2, and I
> only want to NAT pkts leaving virtual router 1, then I think I
> have to somehow force different ct tuples based on which virtual
> router the pkts are flowing through.  I was trying to do this by
> MARKing packets entering a device in a particular virtual router
> and using the mark as part of the tuple....

 From what you wrote I understand you need a sort of separate connection 
tracking for each "virtual router". But I am afraid it cannot be done 
with MARK, because packet classification by the connection tracking 
takes place before the packet reaches the mangle PREROUTING (or OUTPUT) 
chain.