[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: routing + 2 NICs on teh same network

On Tue, 22 Mar 2005 16:20:13 +0200, Chavdar Videff
<chavdar@mr-bricolage.bg> wrote:
> 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 = and eth0:1 =
> My problem is when the above addresses are assigned to 2 NICs
> on the same host, i.e. eth0 = and eth1 =
> Regards
> Chavdar Videff
> --
> To UNSUBSCRIBE, email to debian-firewall-REQUEST@lists.debian.org
> with a subject of "unsubscribe". Trouble? Contact listmaster@lists.debian.org
AFAIK, the easiest way to router traffic between interfaces of the
same subnet is a bridge with ebtables [1]
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.

[1] http://ebtables.sourceforge.net/

Reply to: