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NAT, track next hop config


I am running 12.2 on a 2621 and need to accomplish the following.

1. IP NAT a public IP on the router to a private IP that resides over a lease line on a remote 1601 which connects to s1/1 on the 2600.

2. Verify the route over 2 ethernet devices (1 is a router provided by upstream provider and the other is to a wireless link) is functional before routing to it.

I am currently just using NAT overload for our cache engine and the lease line client at the remote site.

I do not have any control over the router that was provided by upstream provider so I cannot place a static route for any IP addresses to allow them to be seen at that network point. I have a /29 range so I am quite limited.

I was considering using the following


pub ip for NAT overload

ip nat outside


pub ip for remote client on lease line

ip nat outside static to the priv ip of client


priv ip for cache engine and all other internal devices

ip nat inside

I just need to figure out the best way to manage the IP addresses. I also have a PIX for our internal systems, so that will eat 1 IP as well.

I am routing all the traffic from the PIX to the 2600 and then out to the upstream router to allow better use of the cache engine and the ability to route to the alternate provider.

The alternate provider will have to NAT our range on their side or they can issue us a private range to route out their network. In that case we would need to NAT all traffic for that private ip as well.

I have the following equipment available to use if necessary..

5+ 1601 routers

2x 2610

1x 2621

I had also considered doing sub interfaces on the 2610 ethernet ports but my switch only accepts VLAN's on 100mbps ports and the 2610 is 10mbps. I could use the 2621 and accomplish this though.

Thank you in advance..



Re: NAT, track next hop config

You want to do basic load sharing of TCP traffic. You can map a single global IP address to many local IP addresses by using the TCP load distribution feature.

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