Desperately trying to understand Nat
Posted on 2004-08-10
I'm setting up a Cisco 2600 series router that will connect two sites together with a private line. Each client wants to use their own block of IPs to access certain systems, so client #1 has dedicated 12.4.xxx.xxx (not sure why but the customer has chosen to use public IPs)to access customer #2 fileserver and 12.4.xxx.xxx to access customer #1 mail server. Customer #2 wants to translate their IPs to a private IP address before allowing it to route internally. So the picture looks something like this:
Customer #1 ---->12.4.xxx.xxx ---->Customer #2 ---->192.168.xxx.xxx ---->System #1
Call me simple-minded but natting has always been a little confusing to me. I'm not sure where to do the natting here, on both routers or just one? Am I changing the source Address or the destination address? I hope this makes sense.....