Let’s assume this unrealistic scenario in a totally private network. I have two eBGP peer connections coming into my private network, one for Customer A and one for Customer B. Both Customer A and Customer B have identical subnet ranges, for example 10.15.100.0/24. I know I could separate these with VRF's, but lets exclude this for the minute.
If Customer A wishes to exchange data with Customer B then I have a problem due to conflicting subnet ranges. If I were to use NAT, can I establish an eBGP session across a NAT boundary? Furthermore, can Customer A or Customer B have their BGP advertised networks NAT’d to a non conflicting private range of addresses?
If I did use VRF's to separate overlapping networks how could I get these two VRF's to communicate with the knowledge they have the same private networks?
I guess firstly can you establish a BGP session from a BGP NAT'd peer address? Secondly, would I need a transit network behind the customer BGP router to perform the NAT then advertise the NAT ranges into BGP?
The first one will be tricky - would the 2 EBGP peers be using WAN IPs from the same subnet ? If so that may take a bit of experimenting with but i though the requirement was simply to NAT an internal network.
As for natting an internal network this should be relatively straighforward and i suspect altho i would need to test the Natting could be done on the same router that runs EBGP.
Don't mind testing but could you just answer whether the WAN IPs would need Natting ?