My web server fell off the network today. I assumed the onboard network card had died, because all the standard troubleshooting got me nowhere. I couldn’t ping it, it couldn’t ping anything else, and ifconfig eth0 showed it was transmitting, but not receiving anything. And restarting all of my network equipment didn’t help.
So I dug around for a network card and struggled to remember how to configure a NIC in Linux, seeing as that’s something I haven’t had to do in six or seven years. But first I hoped I could just plug in a NIC and it would work, like magic. It happens sometimes.
Not tonight. Finally, I noticed I wasn’t getting any lights at all out of the NIC I plugged in. Dead replacement card? So I unplugged the cable, and the lights momentarily flashed. Hmm. I plugged it into the onboard NIC, and got blinky-blink. The cable works with one card, sort of, and not at all with another. Bad cable? There happened to be a box of cables right there. I pulled one out and noted it was labeled “P120.” Hmm. I had a Pentium-120. I got rid of it more than 10 years ago…. But it was on the network, and for several years as I recall, with no problems. So the cable’s probably good, right? I plugged it in to the onboard NIC and got lights. I went over to the console and tried to ping my router. That worked. So I came back upstairs and tried to access the web server, and that worked.
I remember having problems once, when I first set up the server, and then it started working for no good reason. So maybe the cable’s been questionable all along. It seems strange that it would work for 10 months and then quit all of a sudden, but I’ve seen stranger things. Like a computer that won’t work in one cubicle but works just fine two cubicles down. I know, I wouldn’t believe it unless I’d seen it, either.
Some people these days regard cables as one-use items. Use it once, and if you move things around, replace the cable. Since you can get network cables at Monoprice for a couple of bucks, it’s cheaper in a business environment to just replace cables than to risk something going wrong and having to spend 5-10 minutes troubleshooting it. The cost of even five minutes of unexpected downtime could be considerably more than the cost of the cable.
I’m not at that point, but now I understand.