Re: routing + 2 NICs on teh same network
On Tue, 22 Mar 2005 16:20:13 +0200, Chavdar Videff
> The reason why we do this is because the Cisco router is maintained by our ISP
> and it is configured for the entire LAN. I cannot touch there. And I cannot
> change the LAN address space because there are servers accessed from outside.
> This is the reason why both interfaces of the Debian gateway have addresses in
> the same subnetwork. I use SNAT/DNAT in iptables to masquerade the hosts
> behind the Debian box, so that replies from the Cisco Router pass through the
> Debian box instead of going directly to that host.
> It works if I use 1 NIC with 2 aliases: eth0 = 10.50.40.28/26 and eth0:1 =
> 10.50.40.29/26. My problem is when the above addresses are assigned to 2 NICs
> on the same host, i.e. eth0 = 10.50.40.28/26 and eth1 = 10.50.40.29/26.
> Chavdar Videff
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AFAIK, the easiest way to router traffic between interfaces of the
same subnet is a bridge with ebtables 
In 2.4.x kernels, you must patch the kernel to get ebtables, put it´s
included in 2.6.x kernels.
You can also try ARP Proxy, but I´ve understood you need to keep the
subnet as it is.