In-Depth

Networking Unplugged

What caused this problem the same time daily?

I was a brand-new computer technician, fresh out of a two-year computer technology program at a local community college and working for a local private school. The network at this school was a mix of Ethernet, Local Talk (Macintosh) and Thinnet all hodge-podged together by various people, with varying levels of knowledge, over an extended period of time. A router, bridges, repeaters and hubs connected hundreds of Macs and PCs in eight different buildings. Needless to say, the network crashed often.

Then suddenly, after months of dealing with the same old network issues, the network began to shut down in the science building and library every afternoon around 4:30. The rest of the school would continue to run fine. By eight the next morning, the entire network, including the science building and library, would be up and running again! This was especially annoying for the teachers that chose to work in their offices or the library into the evening hours. It didn’t take long for the complaining to begin.

I examined every inch of the network, including the cabling and the various pieces of equipment, looking for what could possibly be causing this unusual outage. Since indoor Cat5 Ethernet connected buildings, I thought perhaps there was a minute crack in the cabling, and around 4:30 in the evening, when the sun started to set, condensation was entering this crack and preventing the signal from being passed on. This would explain why the network ran fine during daylight hours but not during the long, cold nights (at least to this newbie).

We didn’t have much money in the budget, so hiring a consultant to help me troubleshoot was a last resort. As I was near to pulling my hair out, I decided to try examining the entire length of the network and all devices on it one more time. Figuring two sets of eyes were better than one, I persuaded the school’s head of maintenance to join me.

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We entered the basement of the building where most of our bridges and repeater lived. I pulled over a chair and stood on it to take a good look at the repeater one more time. That’s when the maintenance guy said, "Hey, where is this plugged in?" We followed the plug to an outlet in another room. The repeater was plugged into the same outlet as the water heater, which was on a timed circuit to conserve electricity. The circuit was set to switch off at 4:30 p.m. and trip on again at 6:30 a.m.

The evening maintenance people, when questioned, admitted that they unplugged the repeater from its outlet and plugged it into the timed outlet. They wanted to listen to the radio while working, and the repeater was plugged into the outlet they wanted to use. Needless to say, those folks were warned to not unplug any network equipment without my knowledge. And I wound up looking like a hero for solving the mystery of the network that shut down nightly!

About the Author

Kim Messner, MCSE, has worked in IT for about eight years. She’s currently working as a Lotus Notes administrator

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Reader Comments:

Tue, Oct 28, 2003 nemisis uk

I heard this on another site ! be more original jerk

Thu, Oct 23, 2003 Anonymous Anonymous

Hope it didnt take you more than 10 min. to figure this one out sporto.

Mon, Oct 13, 2003 Rik Queensland

During some office refurbs, we had a Finance server that was in an exposed area. It went down in the evening, but not at the same time, nor every night. Dodgy hardware, faulty power, leprechauns? Turned out to be a cleaner unplugging it, even when we taped the plug into the socket and put a note on it (temptation, or what?). And there was even an 'official' power socket for the cleaner to use, but it was harder to reach.... Helped us get the server away from the 'users' area to a secure cabinet. Sad but true. ALWAYS check the obvious!

Fri, Oct 10, 2003 DPB WI

You go girl!!!!! That's a good one. Working in IT for well over 10 years now and this type of thing will happen to everyone sooner or later. Experience is the best teacher, I'm sure you have learned alot over your many years in IT now too.

Mon, Oct 6, 2003 Kim Anonymous

Yes, I did share the accolades with the maintenance man. By the time we found that problem, they all knew I didn't find it on my own (I was a newbie, I was asking for help). Also, I could have looked at that timed outlet 50 times and still not have known that it was timed. It looked like any other outlet to me. Asking for help is what paid off for me.

Tue, Sep 30, 2003 Ropi Anonymous

my question is--did she share the accolades with the maintenance man or did she just allow everyone to think it was a solo effort?

Tue, Sep 30, 2003 Puteq Anonymous

i say this to anonymous above who said "duh.. first rule.. check the physical" - thats what Kim was doing by checking the cabling, and it was not like the plug was plugged out, just on a timed circuit, not exactly obvious, and yet she did by checking the physical, find this. having worked in IT for many years I always find that end users simply do not understand the troubleshooting process, but if you are an IT person yourself i would have expected more understanding from you of the basics of checking every step meticulously until the fault is found.

Tue, Sep 30, 2003 Anonymous Anonymous

If you have something happening at the same time everyone goes home, look for human causes to the technical problem!

Tue, Sep 30, 2003 Kyle Naeve Dayton, OH

Very good article with quite a humorous cause to the problem. Great work detective! :-)

Mon, Sep 29, 2003 Anonymous Anonymous

Welcome to the real world

Mon, Sep 29, 2003 Anonymous Anonymous

Reminds me of the cleaning lady who crashed the network every night to plug in her vaccum ever night. It was supposed to have happend where I work, but I suspect it is one of those IT old wives tales.

Mon, Sep 29, 2003 TheMan Colorado

U kick his butt?

Mon, Sep 29, 2003 Anonymous Anonymous

yep. everyone has a story like this.

Mon, Sep 29, 2003 Anonymous Anonymous

duh.. first rule.. check the physical

Mon, Sep 29, 2003 Anonymous Anonymous

blah

Mon, Sep 29, 2003 Cliff Tucson

Nice work troubleshooting a typical school network. Well done and your tenacity was very refereshing.

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