NAT : Inside and Outside source

inside & outside are just labels, it doesn't matter which way around you put them. hope that's enough to help

You know the "ip nat inside source list acl_id pool pool_name" command. It says at least that the range of inside (private or local) addresses defined by the acl list will be translated into outside (public or global) adresses defined by the NAT pool. But what special does says "inside source"? After all, the command could be shortened into "ip nat list acl_id pool pool_name" to establish the association between inside (local) and outside (global) adresses.

However "inside source" must have a special meaning because beside the "ip nat inside source" there is an "ip nat outside source" command. So what does both inside and outside source mean? Does the word "source" refer to the source of a transport (TCP) session ?

As a secondary question, what purpose is the "ip nat outside source" command for?

Thanks for any clarification on this subject.

Bernard.

Thanks Doan.

Bernard.

Finally reading

the "ip nat inside source" purpose is to make an inside address appear as a genuine outside address when the packet travels and is seen on the outside network.

the "ip nat outside source" purpose is to make an outside address appear as a genuine inside address when the packet travels and is seen on the inside network

Does it make sense ? ________________________

Yes, that is correct. "ip nat inside source" will translate the SOURCE address as it travels inside (clean side) to outside (dirty side). And it translates the destination address as it travels outside to dirty side.

See