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New Member

ip nat extenable

Hi all, when I do port forwarding on my router, when I use the extenable command, what does this do, cause im sure it still works without it ?


Re: ip nat extenable

? "Extendable" static translations:

The extendable keyword allows the user to configure several ambiguous static translations, where an ambiguous translations are translations with the same local or global address.

ip nat inside source static extendable

Some customers want to use more than one service provider and translate into each provider's address space. You can use route-maps to base the selection of global address pool on output interface as well as an access-list match. Following is an example:

ip nat pool provider1-space ...

ip nat pool provider2-space ...

ip nat inside source route-map provider1-map pool provider1-space

ip nat inside source route-map provider2-map pool provider2-space


route-map provider1-map permit 10

match ip address 1

match interface Serial0/0


route-map provider2-map permit 10

match ip address 1

match interface Serial0/1

Once that is working, they might also want to define static mappings for a particular host using each provider's address space. The software does not allow two static translations with the same local address, though, because it is ambiguous from the inside. The router will accept these static translations and resolve the ambiguity by creating full translations (all addresses and ports) if the static translations are marked as "extendable". For a new outside-to-inside flow, the appropriate static entry will act as a template for a full translation. For a new inside-to-outside flow, the dynamic route-map rules will be used to create a full translation.


New Member

Re: ip nat extenable

for some reason my soho 837 wont let me use the extenable keyword, any ideas why this is ?

New Member

Re: ip nat extenable

can anyone help on this ?


Re: ip nat extenable

If you are running 12.3 or above, it should support it. Please provide more info.

Hope this helps.

Re: ip nat extenable

Hi Carl

Can you revert back with the ios code which you are running over there in your box ?


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