NAT pool with multiple public IP-addresses

daan5000daan5000 Posts: 34Member ■■■□□□□□□□
Hi there

I'm doing some labs with different forms of Network Address Translation. I'm trying to create scenario in which I use a pool of public IP-address so if one public IP-address runs out of port numbers, a second or a third one can take over. I know this is a very common situation in company networks but because I only have GNS3 to practice with I'm not able to test if my configuration works.

On NAT-router I defined an access list of inside local addresses:

NAT-router(config)#ip access-list NAT_INSIDE_ADDRESSES

Next I defined a pool of outside local addresses:

NAT-Router(config)#ip nat pool OUTSIDE_PUBLIC netmask

I enabled NAT on the inside and outside interfaces:

NAT-router(config)#int f1/0
NAT-router(config-if)#ip nat inside
NAT-router(config)#int f2/0
NAT-router(config-if)#ip nat outside

Then I enabled NAT with the following command:

NAT-Router(config)#ip nat inside source list NAT_INSIDE_ADDRESSES pool OUTSIDE_PUBLIC overload

I'm not really sure which IP-address I have to configure on the outside NAT interface. In this lab all addresses between and can be used as public IP-addresses. Does it matter which of these IP-addresses I configure on the outside interface? Or do I have to use subinterfaces for each public IP-address?




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