Continuing on with the last article on NAT, I’m going to look at the ip nat outside source command.

The network in question is:

Bob is on the outside, and r1 is on the inside. I’d like R1 to connect to bob using the address of 5.5.5.5. That means an inside host will be using a different address to connect to an outside host.

R0:

ip nat outside source static 192.168.1.10 5.5.5.5 add-route

This command translates the outside global address of 192.168.1.10 (bob) to 5.5.5.5 and adds a route to R0 to ensure that it gets NATted instead of dropping it because of the router not having route. (See NAT order of operations for the order of operations as a packet goes from inside to outside)

r0#show ip nat translations
Pro Inside global      Inside local       Outside local      Outside global
--- ---                ---                5.5.5.5            192.168.1.10

References

1. last article on NAT
2. NAT order of operations