Trying to troubleshoot an intermittent network problem? Just want to know if you ISP is dropping packets or going down altogether?

So many times I’ve search the ‘net for a simple network uptime script. I always wanted to know the exact time the network went down (and came back up) so that I could track down the cause of the problem. Here is a dead-simple script that will do just that:

#!/bin/bash
## connect_test.sh ##
## This script continually pings an IP address / hostname and reports *only*
## when it is unable to reach the destination.
##
## Example: ./connect_test.sh www.google.com
 
if [[ $1 == "" ]];
then
        echo "Please provide an IP/host to ping"
        exit
fi
 
while [ true ]; do
        p=`ping -c 4 $1 > /dev/null 2>&1`
        if [[ $? != 0 ]];
        then
                d=`date`
                echo "Unable to reach $1 at $d"
                sleep 1
        fi
done

It works best if you open up multiple terminal windows and try to connect to different portions of your network simultaneously. For example:

./connect_test.sh [my neighboring workstation]
./connect_test.sh [my gateway]
./connect_test.sh [my ISPs DNS]
./connect_test.sh [random domain - ie. google.com or yahoo.com]

This way, you can determine exactly where the failure is AND you have a record of the time it occurred. Hope that helps!

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