Subject: weird network outage
To: None <firstname.lastname@example.org, email@example.com>
From: Steven M. Bellovin <firstname.lastname@example.org>
Date: 12/04/2005 01:30:17
I just had a network outage in my house that I can't explain; I'm
posting here because it may be NetBSD-related.
My house gateway is a Soektris 4801, Hellgate, running -current from
two months ago. Its serial console is connected to another -current
machine, Bigboy. All three of the Ethernets on the Soekris are bridged
together; one is connected to the cable modem.
I decided to upgrade Bigboy to today's version. When
I rebooted it, though, I could no longer get out to the net from any
other machine. I suspected that perhaps disappearance of any signal on
the console line had halted the Soekris, so I rebooted it. But it was
hung trying to talk over the network to the cable modem. I'm not sure
how long that would have lasted (and given the hour, I wasn't inclined
to wait too long, but by the time I'd seen this it had been a
reasonable number of minutes. Power-cycling the cable modem brought
I don't think it was coincidence that rebooting Bigboy made things
wedge. I have a plausible explanation for how that reboot could have
wedged Hellgate, via something that looked like a "break" on a serial
console. I have no explanation whatsoever for how that could have
confused a cable modem. Any theories?
--Steven M. Bellovin, http://www.cs.columbia.edu/~smb