Ethernet cable works on some computers, but not others

zgadgeter · December 31st, 2008, 12:28 PM

Hello,
i've tried to search for an answer for my problem, but it's difficult searching for the specific issue.
I've got a switch in the basement at which several connections are made. All of these connections work fine, except for one.
This one cable is about 20 feet long, and ends in a ethernet drop in the wall. I am then connecting another cable into this socket and this goes to a computer. The second cable is about 10 feet long. Now the issue.
This cable works on my laptop, but not on two other computers. When i connect my laptop it gets an address from the main router and works just fine. When i connect one of the computers the network cards register a network connection, but the computers do not get addresses from the router. I show that traffic is going out of these computers, but 0 coming back. I've checked all settings in both computers, and all is ok.
Any tips from anyone?
thanks.

**GroundZero3** · December 31st, 2008, 12:34 PM

are the two computers network cards set to auto duplex?

have you tried a connection repair? What are the network cards?

stroyal · December 31st, 2008, 01:00 PM

are the cards that don't work gigalan

evereddie · December 31st, 2008, 01:16 PM

Is it possible that one of your cables is a crossover cable. Maybe the laptop network system can re-configure and use this but the desktops can't. Maybe the inline connector is a crossover.

Maybe issues with the build of the cables. Try different cables and swap ports on the switch.

zgadgeter · December 31st, 2008, 04:38 PM

Hello all, and thanks for the hints...here some answers:

Both cards are set to auto duplex, and i've tried connection repair. No change

The cards are not gigalan, they are Realtech 8139, and i've downloaded the very latest drivers.

The cables are not cross over. I made them myself, double and triple checked them. I thought at first that maybe i made a mistake in the cables, but they are correct. I've done the whole network installatio in my house, and i've made so many mistakes along the way. After all i've learned i know this cable is correct.

My laptop is a Dell D600, with a giga network card. Not sure whether this does autoswitching.

i'll try swapping ports on the switch...have not done that yet.
thanks so far.

stroyal · December 31st, 2008, 05:38 PM

How did you test the cables. As far as I know, If you don't have some kind of cable tester, the only way to test is by ring out all 8 connections right to the end of the plugs or sockets with a test light or a volt meter for gigalan.

For 10/100 you only have to test the orange and green pairs, provided you are positive they are wired correctly. The ends should be exactly the same, not a mirror image of each other.

zgadgeter · January 1st, 2009, 08:09 PM

Now i''ve tried plugging in the cable into other ports on the switch. No luck with that. Next i'll test the cable with a network cable tester, but am pretty sure of what i'll find: all wires go straight through, most importantly 1, 2, 3 & 6. But i'll test it to make sure.
BTW: no have hooked up another computer with the same model card (but different card), and same story, ie. no connection!
Both computers with this card worked when i hooked them up to another gigahertz switch with a much short cable...

Rootstonian · January 2nd, 2009, 09:42 AM

Does non working one have a static IP assigned to it that's not in your routers subnet; e.g. your router does dhcp for 192.168.1.x and that box has a static ip of 10.whatever (I forget 10. private #)

nemowolf · January 2nd, 2009, 02:06 PM

What cable standard did you use in your house and what standard did you follow for your cable?

zgadgeter · January 4th, 2009, 06:38 AM

Quote:

Originally Posted by Rootstonian

Does non working one have a static IP assigned to it that's not in your routers subnet;

I've DHCP activated throughout, but the two computers that have the issue do not seem to get an IP assigned. The network card indicates that a connection is made. Everytime i pull out the cable from the computer, and put it back in, i get a message saying that the network is now connected. But, when i ipconfig i get no adress assigned. I've tried to ipconfig /renew, but it times out. I've not tried setting a fixed address, but will try that.

Don't know if it is important, but the CAT cable i'm using here does not have a ground shield. It only has the 8 leads. Does that have any significance?

Just remembered. I seem to have had this problem before, with yet another computer (Dell). I could not get a network connection with any of the cables i made myself, even though these same cables checked out ok per liner checker, and in fact worked elsewhere. But, when i connected a purchased cable (with the shielding connected) it worked.
So, anyone know the meaning of the shielding?