NAT Extendable Notes

"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.Some customers want to use more than one service provider and translate into each provider's address space2 upstream service provider with 2 public IP address but same local IP

Cisco notes.

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.

Sample config

ip nat inside source static 192.168.1.1 100.100.100.1 extendable

ip nat inside source static 192.168.1.1 200.200.200.1 extendable