Internet watcher

mrspcs · 10-20-2005, 05:29 AM

I'm looking for a program/script which reboots my server if it has lost the connection to internet.

is there such a program?

sailu_mvn · 10-20-2005, 07:00 AM

check kbandwidth.......its really useful

cs-cam · 10-20-2005, 10:19 AM

Depending on what the server is used for, chances are it won't be running X in which case kbandwidth is out, even if it does what the OP asked which it doens't look like it does.

mrspcs: Best bet would probably to write a bash script to ping an address you know will be up like google.com or something and give it a timeout value. If it fails, reboot. Something like this, run it in /etc/rc.local

Code:

#!/bin/bash

while 1; do
  ping -c 1 -W 3 google.com
  if [ $? -eq 1 ]; then
    reboot
  fi
done

mrspcs · 10-20-2005, 10:40 AM

cs-cam,

Is it also possible to have a script which I can run trough a cron job (then setting it to run it every 5 min or something)?
I'm using webmin / shell to administer the server, so kde apps are out of question

I know how to add cron jobs, but not how to make those scripts, maybe you can help a little

cs-cam · 10-20-2005, 10:44 AM

Heh, oops. That script would take up a lot of CPU cycles, forgot to chuck a sleep in there. You could add it to a cron list, or you could put a sleep line in there to only run the loop once every 5 mins.

Code:

#!/bin/bash
# this doesn't loop so it's good to add to a cron job

ping -c 1 -W 3 google.com
if [ $? -eq 1 ]; then
  reboot
fi

Code:

#!/bin/bash
# this will run the check, wait for 300 seconds (5mins) and check again

while 1; do
  ping -c 1 -W 3 google.com
  if [ $? -eq 1 ]; then
    reboot
  fi
  sleep 300
done

---------
Edit: Also, I'll just explain the ping command in case you're unsure what it does. Might be wasting my time or saving yours so you don't need to ask

That pings google.com once and gives it 3 seconds to respond. If you don't get a response in 3 seconds it assumes you have no connection and reboots. Change -W 3 to -W 5 or whatever if you want to increase the timeout. Run the ping a few times before running the script to see what the average response time is and then add like 5 seconds to that to allow for when you are connected but there is high load on the network or something

mrspcs · 10-20-2005, 10:51 AM

Thanks for your help cs-cam.
I had to change the -W to -i

Code:

usage: ping [-LRdfnqrv] [-c count] [-i wait] [-l preload]
        [-p pattern] [-s packetsize] [-t ttl] [-I interface address]

But I think it works now