Strange wired network problem

At a customers right now and i’ve hit a snag.
They’ve got a bt business hub which is basically a wireless modem/4 port router. That works fine but the problem arises when i try to plug a 10mb switch into it because they want to be able to run upto 6 pc’s and the server from it.
When i plug the switch into the router the lights come on botht the switch and the router but when i plug in one of the cables that go to the plugs in the offices i get nothing. I’ve tested each of the cables to the office plugs by plugging directly into the router and all work. I’ve also tested to the switch with a long patch lead and it works.
All cable is cat5e so should be fine. All bits of equipment work. It’s just the switch wont work with the cables wired into the office.

OK, let me check this,

hub - switch - user (dosent work)

hub - User (works)

what happens if you plug a pc directly into the switch (not via their structured cabling)

Is there any uplink setting on the switch?

errr, I’ll think some more

check with BT that there isn’t a known issue with your brand of switch & BT hubs (long shot)?

Did they mess up the wiring (get some wires mixed up) from the wall plate to where the hub/switch is located? I’ve run into something similar, but it was the patch cables that were made up had a couple of wires swapped.

Ok a brief sum up
pc to hub via stuctured wiring works
pc to switch via stuctured doesn’t work
pc to switch via patch cable works
switch to hub works

Yes switch has an uplink port and have tried it both in that and all the other ports.


From what you’re saying,

pc to switch (via patch cable between pc and switch) to hub works
pc to switch (via structured between pc and switch) to hub doesn’t work

But using the structured wiring going pc to hub works.

Would leave me well…:confused: :whiteflag: :furious:

Are they using Windows XP Home Edition? :smiley:

There pc’s are, the server is using xp pro and also my laptop which i used to test is using xp pro.

Just throwing this out there but:

If I read this right, the wireless modem/router is a 4 port. How many devices are currently plugged into the router? Remember, typically the last port and the uplink are shared, so you can’t have a device plugged into both at the same time. This would mean that you could have 3 devices plugged into the router, then the uplink between the router and switch.

If you’re trying to have a device plugged into port 4 on the router then the switch plugged into the router uplink, that could very well be your problem (could also be trying to use the last port on the switch and the switch uplink resulting in the same problem).

The router only has 4 ports, no uplink port.
Right now the router has the server and 2 pc’s connected with the 4th port being used to connect the switch.
The lights on both the router and the switch show a connection and also if i use a patch lead to the switch it all works fine. Even used a long cable to try it incase it was a length of cable run issue and that still worked.

I’m beginning to think it’s the switch that has the problem as i’ve also used a managed cisco hub instead of the switch and the pc’s would connect ok. Only problem is that the hub is trying to act as a dns server so the pc’s can’t get to the internet and i don’t know the password for the hub to turn that off.
Think i’ll just buy another newer switch and see what happens then.

Yeah, that may very well be the way to go. I know that at work, I’ve got a 5 port Linksys switch at my desk for the desktop pc and my tablet pc. IIRC, it cost about $35 or $40. Just had a look at Staples web site, and I can get the same switch I have now for $29.99. You can get an 8 port for $49.98 and a 16 port for $89.99 and these are 10/100 switches. An 8 port gigabit is $99.99.

If I were doing this and decided to get another switch, i would more than likely get the 8 port switch, then plug everything into that then the switch into the router. That would still leave a few ports available for expansion (including the ports on the router). If they are thinking in the long term that they may add a few more, then get the 16 port one.

If a new switch doesn’t cure the problem, then I don’t know what will, but it sounds as though it should since using a managed hub in place of the existing switch makes the pc’s connect.

New 8 port 10/100 switched ordered and yep i’ll be plugging all the pc’s into it…if it works that is :smiley:

…file this tidbit away…

My router (Linksys WRT54G) can accept either a “straight through” cable from a PC or a crossover cable. (It auto-sense’s the cable. )

Perhaps your customer’s router has this feature but the switch doesn’t.

Thanks for explaining that better than I did Tom. That’s what I was trying to get at earlier in saying that it was “wired wrong”. I believe that the standard in wiring buildings now days is to wire it “straight through”. But if it doesn’t get wired that way, it helps to have a switch that auto senses it and does it’s magic inside so you don’t notice anything.