Greetings:

I was helping someone with trying to share their optonline connection in westchester, NY.
Very strange issue - their cable modem (surfboard 4200) will only work through USB, not Ethernet! And it's apparently the second SB4200 to do this to them!
Here is what they've done - replaced their modem, hooked up other machines, and had a knowledgeable friend come over.
(They were stumped)
Here is what I did - connected it to three different computers, three different routers, none of which can get connected to the Internet. The strange part is that I can get an IP address through Ethernet, and a full range of DNS/DHCP servers that show up in ipconfig, but I can't surf or ping anything, even the servers that show up in ipconfig. I spoke to two different guys at OOL tech support, both knowledgeable and friendly (earn that A+, guys!), and they were as baffled as I was.
I also did hard and soft resets on their surfboard.
And I removed the coax splitter to give the modem a stronger signal.
I own a Surfboard 4100, but it didn't work either, and the OOL tech refused to register it, even for a quick diagnostic. He wasn't being a jerk about it, but he told me it was against policy.
Anyone have an idea as to what the problem is here? This is very strange, and the lack of success with Ethernet is preventing this guy from sharing his connection. I've never seen this before, Ethernet always works grandly when I've helped people with Optonline.
I am going to get either a Toshiba or Linksys cable modem today for diagnostic purposes.
Thanks...

I"m having the exact same problem. I can get connection through usb like I am now but I'm trying to hook a switch up to it. It ways that my ethernet connection is working ok and all that jazz but I can't pink anything. Says "destination host is unreachable" or something to that effect. If you find something out please let me know. Because I'm about to use this computer as a door stop or something.

It's the cable modem. The Toshiba unit works brilliantly both with the PC, and to network in the house.

I'm not sure from your post, but you're not trying to connect the USB and the ethernet at the same time are you?

That won't won't work. It's one or the other.

Did you run the configuration on the modem?

Larry