Wednesday, December 14, 2016

Curious DHCP adventures

At home, I have 3 Windows computers.

About a week ago, one of those computers went insane, and refused to get on the net.

The other two computers were fine, but this one was recalcitrant.

I tried all the various home remedies (restarted the modem, restarted the router, checked my Windows logs, etc. etc.).

Eventually I gave up in disgust and forced a static IP for the angry machine, to get going again.

Then, just by happenstance, I found myself in Michigan, at my in-laws's house, where again there were multiple Windows machines, and one of them went insane and refused to get on the net.

Well, to mis-quote Arlo Guthrie, if it happens once you can just dismiss it as craziness, but this was a real pattern, so I started searching the net, and I found several articles like this.

A number of those articles indicated that people had been successful resolving the problem with a surprisingly simple approach:

  • Restart
  • Restart
  • Restart

(If this sounds like sync three times, well, it sounded like that to me, too.)

It certainly didn't seem like this could hurt, so I gave it a try.

And, after restarting the computer twice, I noticed that the Windows Update Control Panel told me that the computer was now downloading a new Windows Update.

My guess is that something got "stuck" in an automatic download of a Windows Update, and something about that "stuck" caused the DHCP address acquisition process to fail.

But I am having trouble conceiving of why simply restarting the computer several times was enough to "unstick" it.

At any rate, a week later, when I was back at home with my first problematic computer, I:

  • Undid the static IP configuration
  • Watched the machine immediately drop offline and refuse to acquire an IP address.
  • Restarted the computer

And it went online and immediately started downloading a new Windows Update.

So if you're one of those people who is having strange problems getting online all of a sudden (and if you can see this blog), try: restart; restart; restart;

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