nanog mailing list archives

Re: NAT Configuration for Dual WAN Router


From: Rodney Dunn <rodunn () cisco com>
Date: Thu, 15 Dec 2005 14:24:11 -0500


On Thu, Dec 15, 2005 at 08:33:55AM -0600, eric wrote:

[ This is not a plug for a vendor, just operational experience ]

On Thu, 2005-12-15 at 10:49:51 +0100, Peter Dambier proclaimed...

I dont see how the router can NAT to more than one ip-address. So you need
one NAT-router per DSL-line.

I have some experience with the Xincom Twin WAN router. Basically, all it
does is NAT RFC1918 address space (by default) and load balance stateless
TCP traffic (ie. web traffic) over two outbound links. Established TCP
sessions will not fail over, unfortunately, but the device is fairly
reliable and does NAT-T fairly easy. 

Interesting in that I was talking with a customer about something
similar to that today. How can you do nat and failover but keep the
existing TCP sessions alive. Given the two upstreams were doing uRPF
we couldn't come up with a solution.

Rodney


Sure, there's cheaper ways to do this solution without paying for a
blackbox, but there's no moving parts in the device and thus is good for
small offices that have no clue built-in.

- Eric


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