NAT within multiple outside interfaces

[ssa]

Here is scenario:

Router has couple of outside interfaces and also there are 3 static default routes to outsides with different metrics:

1) Fa0 (metric 30)

2) Tunnel0, GRE over Fa0 (metric 20)

3) Tunnel1, GRE over Fa0 (metric 10)

The main idea to use links in order Tunnel1 - Tunnel0 - Fa0

Inside interface is Fa1. It is possible to make NAT within multiple outside interfaces?

- If Tunnel1 is UP - NAT traffic from the inside interface to Tunnel1's IP address.

- In case of Tunnel1 down (default route will be throught Tunnel0 because of specified metric) traffic from Fa1 interface should be NATed via Tunnel0's IP address.

- The same thing in case of both Tunnels in down state, NAT should be done via Fa0 interface.

Is it possible?

Manually it is quite simple to use 'ip nat inside source list 1 interface Tunnel0' command but I could no specify multiple interface here

Thanks

[olorunloba]

You can have multiple outside interfaces. Just specify ip nat outside on each of the interfaces you want. As regards the ip addressing, as you want the natted traffic to be able to fail over to any of the interfaces, it will not be advisable to nat to any of the nat outside interface address. Rather you might create a loopback interface and NAT to it, or create a NAT pool and NAt to it. You would configure your routing such that these loopback address of NAT pool range would be reachable via any of the outside interface.

[ssa]

It is clear about 'ip nat outside', I did in this way before post you see:

rtr#sh ip nat statistics

Total active translations: 0 (0 static, 0 dynamic; 0 extended)

Outside interfaces:

FastEthernet0, Tunnel0, Tunnel1

Inside interfaces:

FastEthernet1

But what should I specify in a global configuration mode to make 'dynamic nat to default route interface' or something like that? I think 'ip nat inside' and 'ip nat outside' is not enough. It might be good idea about loopback, maybe you may specify any examples/links?

[s.uslay]

I also need an example on multiple outside interfaces and single inside interface as well. I need to set up 3 independent NAT for three different companies on the same inside interface. Is there any link on CCO for this ?

Serhat

[ssa]

If I understood this in the right manner it is easier to do this in your case. I guess that 3 diff. companies has separate address space and it can be done with Route Maps, here is link:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a0080087bac.html

[s.uslay]

txs for the link.I'll have a look.

Serhat

[sergey.sysoev]

Any more ideas? Thanks