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Internet, Technology

Virtual rollercoaster of Internet access

August 25th, 2006 by Jeff | 2 Core Dumps

I feel kind of bad apologizing again since that’s how I started the last post (although I think most of you would admit I had a very good excuse for why I hadn’t updated earlier in that case). But I thought I also might take a minute to explain what’s been going on with the blog here, and why it’s been up and down like a hyperactive carnival ride lately.

As recently mentioned, we’ve just moved into the new house here in West Virginia, and we’re still getting settled in. Of course, being the geek that I am, one of the first things that got set up in the new building was the home network. I even came in after closing and before the movers arrived and tested the placement of the wireless access point to see what kind of WiFi signal we’d get. (I’m happy to say I’m getting a stronger signal here than in the house in North Carolina; must be less interference.) We had to wait a few days before the cable company could come in and set up the cable modem, but once they did we were online in no time.

Well, as the observant of you may have noticed, this blog (along with the GPF Store) is actually hosted on my personal Linux box behind said cable modem. (Dynamic DNS is a wonderful thing.) Thus the blog and Store are dependent on this connection and were down in the week or so it took to break the systems down, move them a couple hundred miles, and wait for the cable setup. Not a big deal, as I warned you guys that was coming. As soon as the home network was established, up went Demeter (the Linux box) and the dynamic DNS, and we were back online.

Or so I thought.

I had gotten into the habit of checking in on Demeter periodically during the day from my day job. You know, SSH in, run yum to download updates, check Demeter’s overall health, peek in on the house webcam, etc. However, I started noticing that there were times I couldn’t get in, like the DDNS wasn’t working or Demeter just wasn’t up.

At first I thought it was purely a cable modem issue. Unfortunately, I think our new cable company isn’t quite as reliable as the old one. Judging from the problems our parents have had with their cable modems, it wouldn’t surprise me. My parents’ is ridiculously slow and has a tendency to completely flake out and need the power cycled to recover. Sure, we had the occasional problem with our NC modem, but not the problems we’ve seen here. However, while I’ve caught our cable modem needing a reset a few times, that hasn’t consistently been the problem.

I’d get home after work and notice Demeter seemed to be locked, not responding to mouse or keyboard commands or showing anything on the monitor. The only way to recover from it was to force a hard reboot. Definitely not a good thing for a Linux system, but I have yet to knowingly lose any data. Knowing that we’ve had a few power failures lately (more since we’ve moved into this house than I think we’ve had all year at the old one), I went ahead and sprung for a UPS to make sure Demeter wasn’t going down unexpectedly and failing to recover gracefully. When I caught her doing the same thing after the UPS was installed and known to be fully charged, I knew something else had to be the problem.

So I’ve been pouring over server logs, looking for anything that could be the problem. Nothing seems to show up. I added a small cron that reboots the machine every morning, and that’s helped, but hasn’t solved the issue.

Then I noticed the other day that the machine was up and running, but not responding to the network. The loopback address was working fine, but Demeter couldn’t see the router, any of the other machines on the LAN, or the Internet at large. Every time I tried to look at the network service daemon, the status check would lock up. I rebooted and that seemed to solve the problem, at least for the moment.

I added another cron to go in and restart the networking daemon every hour. That seems to have done pretty good so far, as Demeter seemed to be accessible pretty much all day yesterday. I’ve since scaled back this network restart to once every two hours, hoping that wouldn’t be quite as much overkill. I’d be tempted to suspect that Demeter’s NIC is going bad, but since restarting the network service seems to fix things, it doesn’t sound like a hardware issue. However, I can’t find anything in any log on the system that seems to indicate anything is going wrong, and I’m wondering if the fact that these symptoms didn’t appear until we moved to WV is a coincidence or not.

Anyhoo, I thought I’d let you know what was going on. I don’t have a long term fix for the situation, but my little stop-gap measure seems to be doing the trick at the moment. While I’m a Linux and Open Source proponent, I’ll readily admit I’m not an expert. I’ll keep poking around to see what I can find, and if anything interesting crops up, I’ll try to mention it.

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