Laptop that only works on some connections

[zobbo]

what can I do - dealing with an XP system here...it has a cable modem...and its a wierd problem.

here is the required info:

a friends Dell laptop will not connect to the net....the
modem is working fine as is the cable as I tried it on my own laptop and was able to access the net no problem.

This led me to believe that there was a problem with WinXP so I took it back to my place to check it out...just before I started it working on it I said I would try it connection here...and it worked fine.

So my own laptop will work on this connection via ethernet but the second laptop will not work on this exact same connection...what could be wrong ? i am baffled.

 

[captaincrunch00]

I'd guess that for some reason the connection is loose when you plug it into his laptop.
Get a new cable for sure. Bring yours from your house over and see if it'll work.

Maybe it's just a "restart the modem" problem.

Plug in his laptop with the new cable.
Power off the Laptop.
Power off the cable modem.
Wait 20 seconds.
Power on the modem.
Let it fully power up, let the lights stop blinking.
Power on the laptop.


If that doesnt work, check the IP address that it is getting.
Start->Run->Cmd
Type Ipconfig/all and hit enter.

 

[zobbo]

I tried to restart the modem but I just got same result. I also tried a different cable but to no avail.

when I ipconfig /all - I get "media disconnected" message.

 

[captaincrunch00]

You powered off the modem for a while, then restarted it, WAITED, and then started the laptop right?

Do you have the correct connections enabled in your "Network Connections" under the control panel?

I'm thinking something like: You have it plugged into a connection, that connection is disabled.
You have a second network card, and that is the connection that is enabled and shows as disconnected, the one that you connected it to may not even be there.

What kind of laptop? Inspiron? Latitude?

 

[zobbo]

yes I powered on the modem and turned it off for over 2mins....

All connections are enabled - the laptop works fine with my connection at my house. But when it is plugged in where my friend lives it does not work...to test this connection I got my own laptop and hooked it up his ( which I thought was non-working modem) and it worked fine.

This is puzzling me.

 

[ncotton]

If it is a "CABLE" modem (technical it isn't actually a modem, but we wont go into that), then you need to register the MAC address of the machine with the ISP. This will be in his registration instructions. They do this because CABLE modems work on digital lines, not authorised by the telephone company providing normal synchronous analogue lines. You can register as many machines (unless your ISP limits you), other wise, get yourself a router, you register the MAC address of the router, and assign your router as your DHCP server.

You're account is tracked from traffic emmenating from your assigned MACs. So if you and your friend have the same ISP, and you happen to be using a routed network, and your routers MAC is registered, then all machines behind your router will recieve DHCP address and work fine, but any machine MACs that aren't registered with the ISP will not work infront of a registered router. If you have registered your laptops mac with the ISP, aswell as your router, connecting at your friends house will work, and him connecting at yours, behind the router will work.

This is just the assumption that you are working with a DHCP serving device gateway.


====================

Another issue.....when you plug the cable into the laptop, do you get a connection light and activity light come on above the rj45socket? Does the connection show as "connected" in Network connection properies / system tray

Hope this Helps.

Neil J Cotton
njc Information Systems
Systems Consultant

 

[zobbo]

neil thanks for that. i've got some more info for ye guyz...

This problem has now been replicated! I am in my office
at the moment and just plugged in the ethernet cable - guess what - it is not recognized either. You know when you go to Network Connection and the minute you plug in the ethernet cable the X beside "local area connection" dissappears - well in this case its not disappearing.

As I help out people with their pc problems - I am always using different computers - their systems always recognise the internet connection straight away - not this one??

 

[ncotton]

then the cable is broken, or you are using a cross over cable.

cables between modem and another device need to be cross over cables. from internetwork devices (routers, hubs switches) need to be patch (straight through) cables.

Hope this Helps.

Neil J Cotton
njc Information Systems
Systems Consultant

 

[zobbo]

cc and neil, the problem is now solved. I checked the settings for the internal NIC and power saving was switched on. I disabled this feature and the connection became active again.

Thanks for the input guyz!