Translating overlapping addresses

totts

Has anyone read about this in the cisco press book (doesn't seem to be in Sybex) and like me read it over and over again and end up making up your own interpretaions?

It's basically how NAT can be used to help resolve problems where one company inappropriately uses an IP address registered to a different company and they both use the internet. The problem involves the following... inside local, inside global, outside global and outside local addresses.

I find this subject difficult to get my head around, I think partly because I can't find a clear explanation of what outside global and outside local refer to.

Can anyone provide a 'non cisco press type' explanation to this please?

mikej412

Since Cisco isn't Cisco Press....
Nat: Local and Global Definitions -- Definions, explanation, and example with pictures.

Plus they are honest in that link

These definitions still leave a lot to be interpreted. For this example, this document redefines these terms by .....

totts

Thanks for that link Mike. I've read and re-read it and its cleared it up a bit, but it's a tricky one and as they quite rightly point out it still leaves a lot to be interpreted. An outside local address of 10.10.10.5 keeps springing up which is proving to be a spanner in the works. I'm going to put it down for the moment and read it again later. Perhaps it'll all fall into place then.
Thanks again.

Pash

I wish that cisco would adopt junipers terminology for NAT and get rid of those brain ticklers.

Although to be fair, you have to get around ciscos way of doing things, as your studying for one of their exams.

Outside Global: The address of the last interface where traffic is going out from a company gateway. This address is typically what you will see if you go to web pages like Whats my IP etc. IE what all exterior interfaces of all infrastructures will see.

Outside Local: The Address a company WILL SEE if you try to access their network, it could be NATed on their end and they may see something completely different to your outside global, happens alot.

I can't really explain it better than that, but maybe someone like EDthelad can or Netstudent.

Cheers,