UPDATE 18th April 2010: Netgear have since released a firmware update for the DG834Gv4 which supports NAT loopback. It took them long enough!
Yesterday I made the decision (read: mistake) to update my Netgear DG834G router (hardware v4, firmware v5.01.09) to firmware v5.01.14 – and, as is the way with these things, it brought trouble. After the upgrade I couldn’t reach www.nikrivers.com from the LAN side of the router.
The problem is caused by the way the router handles traffic coming from an internal IP address and destined for the WAN (i.e. external) IP address. In this situation it requires that the router first transfers the traffic from the internal network to the external network, and then immediately passes it back whilst applying any firewall or routing rules that are relevant to incoming external traffic.