[SOLVED] Laptop Connects but Desktop Does Not

[gwheatle]

Relative hardware for this post:
Desktop: Dell D4600
Desktop Network Adapter: Intel Pro/100 VE

Laptop: Dell Latitude D630
Laptop Network Adapter: Broadcom NetXtreme 57xx Gigabit Controller

Router: DLINK DI-604

Issue:
I installed a 40 foot Cat5e cable in my house, connecting the ends to RJ-45 wall connectors. I tested the installation using the laptop specified above. For the test, I connected one of the ports on the router to one of the RJ-45 wall jacks and connected my laptop to the other RJ-45 connector at the other end of the Cat5e cable. The laptop was able to connect to the internet.

The purpose of the cable run, however, was to connect the desktop to the RJ-45 wall connector rather than the laptop. So I disconnected the laptop from the wall jack and using the same cable, connected the desktop to the same wall jack. Although the laptop was able to make a connection to the internet, the desktop cannot. It apparently is having an issue with DHCP obtaining an IP address.

The desktop works fine when conneced directly to the router. Prior to running the cable it was connected directly and worked fine and then after I had trouble with the desktop via the description above, I took it back to the room in which the router resides, connected it directly to the router, and it was able to obtain an internet connect.

So the question is, why can the laptop connect to the internet but not the desktop when they are not connected directly to the router but rather at the other end of the Cat5e cable (the other end of which is connected to the router)? From what I have read, an Ethernet cable can be 100 meters before needing a boost. So I don’t think that is a problem.

Could it be a wiring issue even though the laptop makes a connection? I’ve double checked the wire connections on the wall jacks and they are identical.

I am at a loss. Does anyone have any ideas of what could be causing the desktop not to connect?

Thanks in advance.

[johnwill]

I'm going to guess that it's indeed a wiring issue. You've eliminated both ends, the only thing left is the cable. Did you crimp the connectors onto the cable? The likely suspect is either incorrect paring of the wiring or a bad crimp.


CAT5 Cable Wiring Diagram

HOW TO MAKE YOUR OWN CAT 5, TWISTED-PAIR NETWORK CABLES

[gwheatle]

It was indeed the way the wires were connected. I didn't realize they had to be connected in a particular way. It was just odd that it worked on one computer and not the other. Anyway, thanks for your help.

[johnwill]

The shorter the cable, the more chance that mis-matched pairs will work. The NIC's also have an effect on the results.

Wiring them right is always the best option.