Never hear anyone here that uses double-nat or 'multi nat' on their network. I do on one network, for 2 reasons. 1. improve overall lan security - which basically covers both reasons. 2. separate/isolate part of the network from my computers, example the kids machines, server, DMZ. The idea is to use a second nat router in series to secure your lan network. Traffic would first go through the internal nat in front of your lan and then out through the wan facing nat to the internet. As long as configuration is correct the routers will do there job perfectly. Have a spare router and can justify doing it then give it a go. What do you think?