rv042 and port forwarding-dyndns

Why are you forwarding all ports to .117? The nature of NAT, and more importantly PAT, should allow any traffic that is requested from .117, back to .117 through the link-state session table. You should only have to forward ports that are going to come from un-requested traffic. What I mean here, is that if someone connects to a FTP server you have on 117, they are hitting your external router and the router will not already have a session, and will need to know what to do with the traffic.

As for your issue with external web interface, by forwarding port 80, or whatever port that management interface works on, you have told the router that anything coming to your external IP should be forwarded to .117. This most likely overrides the router actually listening on port 80 for a session to the mgmt interface. The easy way to fix this, is to stop forwarding all ports and only forward the ones you need. If you still have a conflict, see if you can change the mgmt interface port to something you don't need to forward, and make sure it is a 'hole' poked through your forwarding rule. Something like

As for Dyndns, I am guessing you are using that on the router itself and it is not working for the same reason. Put a dyndns client on your 117 box, or find out what port dyndns works on and stop forwarding it.

You should check the Linksys web site

You should check if you have the latest firmware for the rv042 - see the linksys site for that.

Also you may want to check for a Linksys forum - this is a Cisco forum (even though Cisco owns Linksys)