Static NAT explanation, confusion with an explanation

Hello all,

I am reading through the Networking explanation and am at the point, where Static Nat is explained.

There at "Static Network Address Translation (Part 2)" I got confused. In the example with the diagram, there is a Static Nat Mapping.

Private IP 192.168.0.3 maps to 203.31.220.135

this is so far clear. But where I get confused is, that the Public IP of the Router is 203.31.220.134. I assume that in the example there should be also a public IP for 203.31.220.135 in the diagram? Would I be correct with my assumption or did I get something wrong ?

Please help

Thank you

Hello blueeyedguy_moi

Your question is understood. NO, there is really no problem with the diagram. The static mapped IP (203.31.220.135) does not have to be the same as the IP of the BRI0 interface of the router. The mapped IP can be any IP as long as the ISP/Internet routers can route it back to our router.

Do you need to also assign the second IP address to the router's public interface or is this not needed?

It is not needed as long as the traffic is sent through to the router from the ISP.

If you think about it from the point of view from getting a /29 address space, you get 6 valid address, one to the ISP Router. This gives you 5 addresses, one will be assigned your router and if you have setup StaticNat's for the other addresses, then the router will respond to traffic for these addresses.