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Losing Connectivity on Home Network

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Losing Connectivity on Home Network

I run a small home network, on which I have a few PCs, a network printer and an ADSL router. The other day, I wanted to print off a document, so I powered up my printer, but the print failed (Windows reported the failure and I could see the printer light had not flashed to show it was receiving any data). I found I could neither ping the printer nor access its web server. I also discovered that when the printer was switched on I could not ping anything else on my network. I changed the network cable between the printer and the network switch, and went through the process of reinitialising and reconfiguring the printer's network interface, all to no avail. I discovered that if I used a USB connection to the printer it worked fine, so I concluded there must be a fault with its network interface. (I even sent off an email to the manufacturer asking for advice!)
Today, however, with the printer disconnected from the network, I powered up one of my other PCs, only to find the same network problem surfaced: I could no longer ping any of the devices on my network.
As I have a second network switch, identical to the first, I connected this one instead. It, too exhibited the problem, but added a new aspect: if I now connect the printer, on the network switch the indicator light for the printer alternates on and off with the light for the original PC (printer on and pc off, printer off and PC on, etc, etc), and on the PC, Windows reports a network cable is unplugged.
Finally, I replaced the network switch with an old 10Mbps hub. Everything now works, but obviously, the network is down to 10Mbps rather than 100Mbps.

What could the problem be? A faulty bit of cabling?
2 REPLIES
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RE: Losing Connectivity on Home Network

> I run a small home network, on which I have a few PCs, a network printer and an ADSL router. The other day, I wanted to print off a document, so I powered up my printer, but the print failed (Windows reported the failure and I could see the printer light had not flashed to show it was receiving any data). I found I could neither ping the printer nor access its web server. I also discovered that when the printer was switched on I could not ping anything else on my network. I changed the network cable between the printer and the network switch, and went through the process of reinitialising and reconfiguring the printer's network interface, all to no avail. I discovered that if I used a USB connection to the printer it worked fine, so I concluded there must be a fault with its network interface. (I even sent off an email to the manufacturer asking for advice!)
> Today, however, with the printer disconnected from the network, I powered up one of my other PCs, only to find the same network problem surfaced: I could no longer ping any of the devices on my network.
> As I have a second network switch, identical to the first, I connected this one instead. It, too exhibited the problem, but added a new aspect: if I now connect the printer, on the network switch the indicator light for the printer alternates on and off with the light for the original PC (printer on and pc off, printer off and PC on, etc, etc), and on the PC, Windows reports a network cable is unplugged.
> Finally, I replaced the network switch with an old 10Mbps hub. Everything now works, but obviously, the network is down to 10Mbps rather than 100Mbps.
>
> What could the problem be? A faulty bit of cabling?

Hi,
You clearly have a good understanding of networking etc but I wonder if you have checked your machines for viruses it sounds very suspicious. The thought that I had was one of those nasty viruses (name escapes me right now!)not long back infected printers & screwed up your network! I
am not saying its a certainty but just a thought that you should definitely give some serious attention too! do check it out?

Ivan


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RE: Losing Connectivity on Home Network

> The thought that I had was one of those nasty viruses (name escapes me right now!)not long back infected printers & screwed up your network! I
> am not saying its a certainty but just a thought that you should definitely give some serious attention too! do check it out?
>
Well, I checked out the CERT advisory notices, and there were a few network-printer related ones, although none appeared to apply to me.

I had thought there'd be a single cause for my problem, but on following through, it seems there may have been multiple things wrong. I'm fairly certain the integral print-server on my printer is on the blink, for it does not always work at 10Mbps either, and sometimes now it fails to initialise when the printer is switched on. A replacement module costs about £150 - it's cheaper to buy a standalone print server, more flexible in the long run, though not such a nice solution.

I also found there was a dodgy cable. By jiggling it near one of the RJ-45 plugs, I could make the indicator light on the switch toggle on and off. So I chopped the plugs off both ends of the cable, and connected new ones, which has given a much more positive connection.

Finally - and this was (perhaps surprisingly) the most difficult fault to find - the external power supply for the switch itself. Both the orginal switch and a replacement (using the same power supply) gave faults after a few minutes use. Having connected a new power supply, they both work satisfactorily for hours on end.

Hopefully, that's all the problems located and resolved, and the network will stay stable again for a few more years...