Strange problem with cable modem setup

[Ksyder]

I was trying to fix a broken internet connection (A WinXP laptop directly hooked up to a cable modem) and it would release/renew an ip address but would not get online. If I hooked up my own laptop to the cable modem and reset the MAC address for my machine it worked fine. The addresses assigned were different in each case. The broken laptop got an ip address starting with 10.226... and my machine got 192.168... (I don't remember the exact addresses) I am not sure if the default gateway or subnet masks were different. I continually tried to release/renew the ip address of the broken machine and the addresses never worked. If I plugged the DHCP addresses that were given to my computer into the broken one as static, the machine would be able to get online. I ended up setting up the broken laptop and assigning the valid ip address that was given to my machine as a static ip on the broken one. That was working fine, but I am concerned about the DHCP lease expiring and breaking the static ip configuration. Any thoughts on this? Hopefully someone has seen something like this before.

 

[kevnich2]

Call the ISP? Setting up the DHCP IP as a static IP is a very bad idea as once the lease does expire (a few days usually), it'll now get used on another customer and could easily cause problems on their network

 

[JackMDS]

krwilsonn, you might be mixing some stuff and Not being aware of the whole setting.

Both 10.226... and my machine got 192.168... are private IPs and have nothing to do with the ISP.

Some place in the setting there is a Router.

 

[Ksyder]

This is their ISP...

http://seniortv.org/

It's at a retirement community. Each resident has a cable modem and in this case a laptop was directly plugged into a cable modem. I would assume then that the router you are referring to would be the one that is at the headend.

"Your SeniorTV cable headend is connected to the Internet using either a T-1 or DSL telephone line. A broadband router is located in the SeniorTV cable TV headend which shares the high speed internet connection with everyone on your cable system using the existing coaxial wiring. This is the same method used by large franchise cable TV operators except the cost is much less. Your cable TV wiring system and amplifiers are upgraded or replaced for 2-way capability so that the cable TV channels and computer downloads are delivered forward from the headend to the resident computer, and the resident's request or "send button" is delivered in reverse back to the headend. Utilizing a good wiring system is important."

here is more information directly related to the internet service in particular.

http://seniortv.org/internet.php

 

[Aarondeep]

There is a cablemodem for each resident? You are getting private IP adresses, sounds like you are connected to some broadband router. I would contact the ISP for support.

 

[JackMDS]

I agree with the posters above. I would not mess up with the system, call the provider.

 

[Ksyder]

Everyone there that has broadband has a cable modem, presumably so they can use the existing coax wiring for both the cable service and HSI. The strange thing about it is that each computer got a completely different IP address. I could go back and forth re-syncing each laptop to this cable modem and the broken machine would get a non working IP, and then the working one would get a good IP and then I would switch the modem back to the bad laptop and the IP address would not work. What I was really getting at here is I thought there might be some odd registry key or something on the broken machine that causes it to use a different DHCP server or something. Networking is not my specialty so when something odd like this happens I'm not prepared to know how to deal with it.

Thanks for the info and suggestions guys.