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New Member

NAT Interfaces

If you have a router with 2 interfaces - 1 inside, 1 outside.

For a packet to get translated "say inside source for packet going in the direction of inside to outside", does the packet have to pass thru both an inside and outside interface for a translation to work? or as soon as it sees the inside interface, it gets translated?

Many thx

New Member

Re: NAT Interfaces

OK, I have now found the statement :-

"In order for NAT to take place, a packet must be switched from a NAT "inside" defined interface to a NAT "outside" defined interface or vice-versa. "

but where in fact is the packet header changed on say an inside source static? If the packet was coming inside->outside, as it needs to know that it has gone from inside->ouside, the packet must be translated on the outside interface, or does the RP check the routing and check that the next hop interface is config'd with ip nat outside and it does the translation on the rp or inside interface.

Confused - I AM. Think i may need pictures on this one :)