I have four router (See Visio diagram attached)
Router A, B, C and D. On router B i have interfaces Gi0/1 which is configured as "ip nat inside" while the Multilink 1 is configured as "ip nat outside", GRE Tunnel 0 is configured with NO NAT.
The Senerio
I want to route RFC1918 IPs between Routers A and D via the Tunnel 0
I am doing NAT on Router B to get to the LAN with a rouable IP addresses.
Success
When traffic flows between LAN Public IP
(Non-RFC1918 Routable) and WAN RFC1918 NAT Translate OK
Problem
From Router D when LAN RFC1918 route traffic thru the Tunnel 0 to Router B I do not want NAT to take place on the Multilink 1. I want real IP address to route through however NAT take plase too.
Question
Knowing that i do Static NAT on Multilink1 How do i allow NAT from LAN
Public IP (Non-RFC1918 Routable) to WAN
RFC1918 10.10.10.10 and also not allow NAT to 10.10.10.10 if traffic originated from LAN RFC1918 via the Tunnel0
Thanks
Adeolu