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NAT Query


I'm wondering -


If I have the following - Site A and Site B separated by WAN connection say MPLS.


Site B has no Internet connection / or associated External IP addresses.

Site A does have Internet Breakout / External addresses.


Is it possible for me to setup an inbound NAT at site A for a LAN address at Site B to be accessible externally?


Or do NATs have to be used locally to the site the external address terminate at?

Hall of Fame Super Blue

There is no requirement for

There is no requirement for NAT to be local to the site.

As long as the real IP is routable from site A then it should work fine.



Thanks Jon,And it's all setup

Thanks Jon,

And it's all setup in exact the same way as If it was a NAT for a local address? Nothing special needed? Apart from the routing in place?

Hall of Fame Super Blue

No, nothing special as long

Nothing special needed.



Hi Jon,Apologies digging up

Hi Jon,

Apologies digging up this one again -

If someone externally communicates to the inside Server address at Site B through the NAT from site A's external addressing. How is the return traffic from Site B address handled? Would Site B need to have a default route pointing to Site A to be able to get out to the Internet from Inside to Out?

E.G - External Static Nat at Site A for a host in Site B (Sites separated via MPLS WAN). 

Someone from Outside contacts the external address - it hits Site A NAT which routes to inside address at Side B. 
For Site B to then communicate back - does this need to know where the public address space sits and have a route to it through Site A.

Hello You can nat from an



You can nat from an public routable outside ip address to a none routable inside address

Stie A

ip nat outside static (site B public ip) (site A private ip)




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