I challenge ANYONE to figure this out…
Before I begin my explanation of the problem, please understand that at this time the network\internet WORKS. However, the method in which I employed to get it to work is very….strange. In short, I am wondering how I have connectivity at all at this point. Here we go…
I was called out to one of our buildings the other day after they had just been without power for around 5 hours. Staff inside had no internet connection, after the power was restored, of course. I first checked outside; we employ a wireless point to point system offered by Airaya. (www.airaya.com) So my first inclination was that the antenna had been knocked out of alignment. This proved to be true, and after adjusting the antenna a little I was able to plug into the bridge of the antenna and access the internet.
Down in the wiring closet, things were not so simple as the rest of the building was still without internet. The bridge I spoke of resides in the attic, so we have a PoE connection carrying the data and power up to the bridge through Cat5. This was put in place so that trips to the attic would not be necessary to power cycle the bridge – it could easily be done from the closet. The cable coming from the attic first hits a small patch panel (don’t ask me why, i didn’t install it, and to me looks like a waste of patch cables) and from that patch panel the PoE injector hangs, then the Cat5 coming off the injector connects to a Netgear ProSafe 24 Port 10/100 Switch (Model: JFS524) Link: “http://support.netgear.com/product/JFS524” – From the switch we have a convoluted mess of cabling that in some cases goes back to the patch panel, others go out to their respective places on the network, mostly workstations and printers. Don’t worry about the mess of cabling because it becomes obsolete when I explain the problem….in short, the 24-port feeds the whole network from the internet coming in on port 1.
The problem is, when I plug my laptop into the LAN port of the PoE injector, I get internet just fine. When I plug said PoE into the switch, then plug my laptop into the switch, i get nothing.
Now, since I can get the internet from the interface on the PoE, I am left to believe the network hardware up to that point is fine. This includes the antenna, bridge, PoE, all wires in between, and the hardware back at the transmitter tower…the internet works.
Any troubleshooter worth his or her salt would now argue, “It’s the switch stupid!! Get another one!!” I’m way ahead of you. In fact I tried 3… Same problem, but, same brand, same model…JFS524. I hardly think that matters though, stay tuned.
In order to simplify the problem, when trying the new switches (by new I mean they just came out of the box and plastic) I eliminated ALL other connections, besides the Cat5 from the PoE injector (the internet) and my laptop. Still nothing. I got the internet cable plugged into one port, my laptop plugged in another and I got nothing…on three different switches. When I eliminate the switch, and plug directly into the LAN port on the PoE injector…TADAA!!! Internet.
Remember, these are dumb (smart?) switches. NO configurations.
I have never come across this…but I don’t have much experience with PoE – so I was blaming it the whole time.
HOW I FIXED IT:
I found a small 5 port switch we had sitting around (http://homesupport.cisco.com/en-us/wireless/lbc/ezxs55W). I brought it over to the closet, connected the “Internet” line to it, connected my laptop to a free port on the small switch, and TADAA!!! Internet.
Ok, the easy thing would be to then connect all the lines to the little guy, and be done with it. Not so simple. This little device does not have enough ports for everyone in the building. So, in a last ditch effort, and out of sheer morbid curiosity, I link the 2 switches together….TADAA!!! Internet. For EVERYONE.
Yes. Somehow attaching the internet line to the little switch, then the little switch to the big switch fixed all internet connectivity for the entire building.
My question is HOW? All signs seem to point at the 24-port being bad, however that is obviously not the case. I also thought DHCP was to blame, but the IPs on each machine are static. The DNS server was also checked, rebooted then rechecked…no problems.
If nothing else, I hope this post at least helps ONE other person…and if somebody knows WHY this is happening or has run into it before I would love to hear it.
-=K=-
