Could any anyone confirm to me which of NAT or CEF takes precedence when both are configured on a router.
I have CEF enabled globally to load balance Internet traffic between two ISP connections on a per source/destination combination basis but also NATed (dynamically & statically) inside addresses to the 2 ISP connections using route maps. I would like to know what happens when a traffic is subject to the 2 features which is first consulted. Does the traffic get NATed first before being CEF switched or the other way? I have assumed until now that it is first CEF switched before being NATed. I however would like to be certain. I am especially concerned about static NAT where a connection was initated from outside through one of the ISP interfaces and a translation has already been created. Now since CEF sees the 2 paths as equal for the reply, does the NAT translation take precedence and therefore forward the reply back through the ISP interface the request came in from since a translation already exists even if CEF per source/destination algorithm prefers the other ISP connection?