Networking

TechRepublic members speak out on quirky networks

Ever have a network problem that just did not make sense? TechRepublic members speak out about the ghost in the machine.


Have you ever had a network problem that was just completely odd? If so, you’re not alone. We asked TechRepublic members to tell us about network quirks they’ve solved, and here is what they had to say.

The ladies room is an administrator’s worst nightmare
Would you believe that a ladies room would cause a network to seize up? It’s possible, as TechRepublic member Joerg Bungert found out.

“One of my customers, a small company with 20 employees, explained an interesting problem that the network was having: ‘Every time one of our female employees is in the ladies room, we have network problems. Network errors occur, and sometimes even the server stops.’

“My first thought on the subject was, ‘They’re kidding me.’ However, it turned out that the problem was indeed very serious, so I went to the company to have a look at the network.

“The solution was as simple as it could be: They had one 10base2 cheapernet segment with 160 meters length. The installation had two minor mistakes:
  • First, both ends were terminated, but one (and only one) was not grounded. Remember, each end has to be terminated. That was correct, but only one end has to be grounded.
  • Second, the RG58 cheapernet wire crossed two neon lamps in the ladies room. Every time the light was switched on, the ignition of the lamps caused the network to experience errors.

“The solution to the problem was simple. I changed one of the 50-ohms terminators to a terminator with grounding and chose another route for the cable, which was only two meters away. Afterward, we had proper performance and no faults anymore.”

It helps if your building is wired correctly, you know
If you’ve ever had to crimp cat5 cables, you should know that certain wires have to be in certain spots on the pins before you crimp. The wires on one end have to match the ones at the other. However, David Thomas explains that whoever installed the wiring in his building must not have known that this particular fact was important:

“A particular node on a 10baseT network started failing to log on. There were no link lights, so I inspected the plugs on the end of the cables. There were no jacks or patch panels, so I assumed it was just the cable and two plugs.

“While inspecting the first plug, I noticed the 3 and 6 pins were not paired, so I immediately decided to re-terminate both ends. It still did not work. I then changed out the NIC in the workstation. Unfortunately, there were still no link lights.

“I strung a temporary cable and it worked fine. I proceeded to replace the faulty cable. I climbed up above the ceiling and strung a new cable. Afterward, the computer worked fine. While removing the old cable, I discovered that it was actually in two pieces with an RJ45 junction block in between. The wire colors were wired to completely different pin outs on the two plugs. I then looked at the plugs I cut off previously and found they were different as well.

“In the end, I was glad I discovered this problem. With further investigation I found a similar situation with three other cables in the building. After showing all of this to the owner, he authorized a completely rewired Level 5 cable plant with patch panels and jacks.”

A monitor and fan don’t mesh too well
When you were younger, did you ever put a magnet next to your television screen? It made the screen do all kinds of weird things. Believe it or not, a fan can have the same effect on a monitor, as Brandon Baker explains:

“A few years ago, when I was a desktop support tech at an engineering company, I received a call from an electrical engineer who was experiencing monitor problems. His monitor kept losing vertical stability, like the old TVs with foil ears and scrolling pictures. I walked over to check it out and immediately thought the CRT tube was going, so I decided to replace the monitor. Simple problem solved, right? Wrong.

“The problem didn't disappear, and I replaced the monitor with another spare. The screen kept scrolling, so I spent 15 minutes checking cables and video settings. Maybe the guy had his refresh rate out of sync. Nope. At this point I'm getting discouraged, so I ripped open the PC case and replaced the video card and the monitor with more spares. I rebooted and set the resolution to the lowest setting, but the screen kept rolling and rolling. I grabbed my head in frustration.

“I had spent 45 minutes on the workstation, and the engineer was starting to joke about taking the day off, which didn't do much for comic relief except elicit a nasty look from me, so he left to peruse the coffee maker. I sat back to contemplate my situation.

“I turned off the computer to replace the video card again, and that was when it hit me. There was a low, mechanical buzzing in the background. It sounded like it was coming from another cube, so I decided to peek over the cube wall and almost lost my temper when I discovered the cause of my troubles: the engineer's neighboring CADD designer had placed an electric fan against the wall and opposite the engineer's monitor.

“Didn't anyone teach engineers—and electrical engineers to boot—about EMI? If they did, it must have been right alongside the underwater basket weaving class. I relocated the fan, the engineer came back from lunch, and he thanked me for my diligence.

“The moral of the story is a $10 fan from Wal-Mart can wreak havoc with a $1,200 workstation, stall an $80/hour engineer, and bring a PC tech to the brink of insanity if it's in the wrong place at the wrong time.”

Sometimes there just is no answer to solve your problems
What happens if you run across a problem that you just can’t figure out? Blair Christensen faced this dilemma and came up with a solution that solved his problem. However, he still doesn’t know how the problem was fixed.

“I used to work for a company where one user would consistently complain about having problems with the monitor in his cubicle. The cubicle was located in the center of the sales floor of about 30 other sales reps, and was about 15-20 feet from a window. I was called up to investigate and found that, yes; the monitor did behave erratically, as the screen would shift slightly every now and then in a distracting manner. I noted the specifics of the problem and decided to try adjusting the refresh rate of the monitor. After adjusting the refresh rate, it appeared to be okay, so I congratulated myself and moved on. I got a call back the next day, complaining that that problem had returned.

“I went back to the computer in question and tried several other refresh rates in Windows, as well as changing the base refresh rate in the BIOS. I even tried a variety of custom and generic monitor drivers. Nothing seemed to work.

“Then, as an experiment, I switched out the monitor with an identical one from a temporarily empty cubicle nearby and reset the original refresh rate. Again, this proved to be useless.

“After ruling out the monitor as the source of the problem, I began to carefully examine the environment. There were overhead fluorescent lights on the peaking ceiling, and I examined the power cables to verify they were not running across the monitor cable. I looked at the monitors in the cubicles surrounding the one in question and found nothing amiss. I was bewildered.

“I then tried to substitute the PC from another cubicle, which was not in use. It was of the same brand and model, and it too exhibited the erratic behavior! The PC that had been exhibiting the flicker now worked perfectly in the new cubicle, even though it was within 10 feet of the original location.

“I scratched my head and tried a slightly different model. It also exhibited the strange behavior, even with a monitor of another brand.

“I was truly stumped. I had searched the Web for similar occurrences and found nothing useful. As a last resort, I switched out the whole PC/monitor setup with a brand new PC, which had just been purchased. For some reason, the flicker disappeared. I envisioned in my head the Dilbert cartoon with ‘Saint Dogbert’ as he waved his scepter and cried, ‘Out! Out you demons of stupidity!’ To this day, I have no idea what the true source of the problem was.”
Have you experienced any weird or unusual network quirks? If so, we’d love to hear about them! Feel free to leave a post below or send us a note.

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