Cable modem connection woes

[ffpm757]

Hi folks,

Working on a network installation for a friend, and I'm absolutely stumped. They're running WinXP Home with SP1, and besides device drivers that's the only software currently installed (said friend just did an fdisk and format with a clean installation of the OS). Here's the issue that I've run into: when connecting the cable modem directly to the computer via ethernet, I can't hit the ISP's DHCP server. If I connect the modem via the USB port, it works just fine.

In an attempt to eliminate some variables, I've replaced the cable modem with a new model from the ISP's list of recommended products, and registered the MAC with the ISP. Same issue- no dice with the ethernet, works fine with USB. I also attempted to access the internet from my laptop by connecting it to the modem via ethernet (to eliminate the NIC as a problem), and was unable to connect to the DHCP server. I don't think there's anything software related jamming up the works, since we're working from a clean installation of the OS. I contacted the ISP's tech support, and they indicated that everything on their end is working OK.

I'm stumped, and would be extremely receptive to any advice or information you might have... I'm about to start ripping hair out over this, it's so frustrating. Thanks!

 

[yinan]

Have you tried setting a static IP address on the network card? For instance use the same IP that you get from DHCP when plugged into the USB connection?

 

[JackMDS]

This is not a direct solution to the problem.

I would install cable/DSL Router even if the connection is used by one computer only.

A Router would keep the connection live, would add protection to the Connection, and the computer would work smoother.

Once you get the Router you have to clone the MAC address that is registered with the ISP to the Router; WAN side.

 

[ffpm757]

Jack-

That's actually the end goal of all of this: to have a wireless network for a laptop and a wired connection for the desktop, both running through a router. Unfortunately, for whatever reason, I can't get the desktop to hit the DHCP server when connected to either the router or the modem itself via ethernet. That issue also keeps me from completing the router's installation and setup program. The old modem gave me the same issue, so I replaced it (to no avail). I just removed the router from the picture to simplify the troubleshooting process. The computer simply won't talk to the modem (or vice-versa) over ethernet, and it's making me a little nuts.

Yinan-

I'll keep that in mind and give it a try the next time I'm up there. If it works, it'll be a step in the right direction.

Thanks!

 

[4836348435]

Are you using cross-over cable to connect to the modem? If so, you may need to switch to standard cabling.

 

[ffpm757]

I'll make sure to double-check the cable. I used the cable that came with the modem, so I just assumed it was of the standard variety rather than a cross-over.

 

[JesseKnows]

The PC should tell you that the cable is unplugged, if you use crossed instead of straight.

Is the modem set up per the network requirements, i.e., could it be PPPOE and you are attempting DHCP?