Scheduling Reboot of Motorola Cable Modem

UPDATE: This no longer works for me because a recent firmware update removed the Restart command from the web interface.

Periodically my Motorola SURFboard SB6141 cable modem stops talking to the outside world. I don’t know why, but restarting the modem fixes it every time. Rather than having to regularly power-cycle it by hand – or, heaven forbid, buy new hardware – I decided to schedule an automatic reboot.

The modem itself doesn’t have a facility for automatic reboots, but it has a web page with a button to restart it! <http://192.168.100.1/cmConfig.htm> So all we have to do is automate the clicking of that button.

If you have this model, or a similar one, this command should work. Just paste it into your terminal/console program and hit Enter, and see if you temporarily lose connectivity to the Internet. If you do, then it worked:

/usr/bin/curl http://192.168.100.1/reset.htm -G -d reset_modem=Restart%20Cable%20Modem > /dev/null

Once you verify it works for your modem, add it as a cron job. Mine looks like this, running daily at 4:30am:

30 4 * * * /usr/bin/curl http://192.168.100.1/reset.htm -G -d reset_modem=Restart%20Cable%20Modem > /dev/null

Tips:

  • The only real dependency is that you have curl installed. On Mac OS X, CentOS, and Debian it lives at /usr/bin/curl but if you’re using a different distro/OS you’ll want to make sure the path is correct.
  • Verify the IP of your cable modem is correct. For most/all Motorola models it’s 192.168.100.1 but try Googling yours if that doesn’t bring up a status page in a browser.
  • If the IP is correct, make sure the values passed by the restart button are the same as my example. (Go to the page that has the button, make sure that URL matches my example, then view source to make sure the name and value of the button match.)