I would like to configure two Cisco 2801 using IPSEC/IKE. Both routers are connected to the internet via DSL lines. The DSL line have RFC1918 addressing on the LAN side where the routers connected to facing the internet. I can do NAT on the DSL modems.
Do the Cisco IOS 2801 routers allow to configure site-2-site VPN with NAT traverse?
Here is a model of physical/IP setup:
LAN<->2801<-Priv IP->DSL Modem<-Internet->DSL modem<-Priv IP-> 2801<-> LAN
Yes you are good to go only if one or both of the sites has a IP address which is statically natted with the private IP address. Most of the implementation of IPSec on ISR support NAT traverse so that should not be a concern