I got Vonage back in February, borrowed their LinkSys router, model #RT31P2. Since then we've gotten rid of Vonage and therefore must send the router back, my problem is, when I directly connect my lappy to the cable modem (Motorola SB5101), it won't connect to the net, won't acquire an IP, and so forth. But as soon as I hook the router back up, the internet fires up fine... my system is set up for dynamic IP and such... Any advice would be greatly appreciated. I'm at a loss. I just don't want to send the router back until I know I can get online without it... and I'd rather not pay them for it.
(btw, I set up port forwarding in the router so that friends could connect via SSH, but I've since disabled all of that, and still no luck).
Thanks in advance.

When you're connected to the router you're returning to Vonage, what IP address is assigned to your Fedora machine, and what is the gateway address? The command "ipconfig -a" will reveal it.

The key here I think is to find the IP address of your cable modem. While connected to the Vonage router, issue the command "traceroute 64.233.187.99" (which is one of google's web servers) and see if you can identify your cable modem. It should only be a hop or two away from the source.

You might also try cycling the power on the cable modem in an attempt to purge it of any possible cached MAC addresses, but only *after* you've removed the Vonage router and connected your laptop directly to the modem.

Disclaimer: I don't have a cable modem, so none of the above may work. But it's how I'd proceed if I were you.

Good luck.

More than likely it is a mac address issue. Cycle the modem or may need to contact your provider to add the laptops mac to your service. Make sure you have your firewall turned on before connecting to the internet. Your best bet is go out and get a cheap wired router. Usually $30.00 or less. Then before sending back your other router get the mac address it was using on the wan side and enter that into the new router. That should take care of it.

Hope this helps.
Brian1

It could also be that the router is using a static address for the cable modem (the "red"/WAN side), but providing dhcp addresses to clients (the "green"/LAN side). If this is the case, then you need to find out what address the router uses for the cable modem and statically give the laptop an address in the same range when you connect directly to the cable modem.

So, for example, if your router thinks the cable modem is on 10.0.0.1 with a subnet mask of 255.0.0.0 then you need to give your laptop and address between 10.0.0.2 and 10.255.255.254 with the same subnet mask.

ipconfig -a basically came back saying no such command exists... and i tried the traceroute, but being fairly new to linux, i have no idea what i was looking at when it brought back results... thanks for the help anyway. guess i'm just screwed.

The full path is: /sbin/ifconfig
A regular user usually does not have /sbin in its path. If via su then su - will use roots path instead of the regular user path.