Weird problem/simple fix:new 16port switch failure due to looped back cable
I fixed this, but it was such an odd problem, I wanted to post the fix.
A client called me complaining that their Internet connection sometimes stopped and they had to power cycle both the router (understandable) and 8-port 10/100 hub (not understandable).
To save time and money (because my hourly rate is so high it's often cheaper to replace suspect equipment than screw around with it then determine it needs replacing anyway), I replaced the router and the hub, the latter with a 16-port 10/100 unmanaged switch (with each port having autosensing uplink capability). I transfered 12 cables from the old hub and router to the switch.
WEIRDNESS:
I couldn't ping the router unless the PC I was using was directly connected to the router (i.e., bypassed the switch). I noted the lights on the switch were spazzing out (blinking like mad (blinking very quickly).
I've installed at least a hundred switches and hubs over the years, and I never had this problem.
I unplugged every cable from the switched except for the router's and PC's I was using. I could then ping the router and surf the web.
I thought there must be a network device in the building that's freaking out and sending blathering garbage and causing the switch to malfunction.
My client recently removed a VOIP server appliance, and I suspected something related to that.
The Ethernet cables were very tangled in the wiring room, but I traced the cables and found one that was looped back into the switch (i.e., both ends of the cable were plugged into the same switch). It had been this way in the hub, too, and I showed my client this.
He had seen a dangling cat5 cable and decided to plug it into the hub not realizing the other end of the tangled cable was already plugged into the hub. The hub apparently was more forgiving than the Netgear 16port switch but still had problems requiring it to be power cycled.
FIX:
Removing the looped back cable fixed the problem. The switch is better than the hub any way and my client is happy.
A client called me complaining that their Internet connection sometimes stopped and they had to power cycle both the router (understandable) and 8-port 10/100 hub (not understandable).
To save time and money (because my hourly rate is so high it's often cheaper to replace suspect equipment than screw around with it then determine it needs replacing anyway), I replaced the router and the hub, the latter with a 16-port 10/100 unmanaged switch (with each port having autosensing uplink capability). I transfered 12 cables from the old hub and router to the switch.
WEIRDNESS:
I couldn't ping the router unless the PC I was using was directly connected to the router (i.e., bypassed the switch). I noted the lights on the switch were spazzing out (blinking like mad (blinking very quickly).
I've installed at least a hundred switches and hubs over the years, and I never had this problem.
I unplugged every cable from the switched except for the router's and PC's I was using. I could then ping the router and surf the web.
I thought there must be a network device in the building that's freaking out and sending blathering garbage and causing the switch to malfunction.
My client recently removed a VOIP server appliance, and I suspected something related to that.
The Ethernet cables were very tangled in the wiring room, but I traced the cables and found one that was looped back into the switch (i.e., both ends of the cable were plugged into the same switch). It had been this way in the hub, too, and I showed my client this.
He had seen a dangling cat5 cable and decided to plug it into the hub not realizing the other end of the tangled cable was already plugged into the hub. The hub apparently was more forgiving than the Netgear 16port switch but still had problems requiring it to be power cycled.
FIX:
Removing the looped back cable fixed the problem. The switch is better than the hub any way and my client is happy.
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