Monitor for abnormal bandwidth use, ignore short spikes, store five minute values

From Internetworkpro

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This bash script will send FAIL or OK to an html page (to monitor) based on the value of in_convert and out_convert which are Mbps traffic rates converted from polling bytes in and bytes out from a router.

If you were to look at the snmp graph of the traffic, you find where the peaks of the hills are, and use a number slightly over that, then set the timing on the monitor checking for OK or FAIL to ignore the short spikes.

#!/bin/bash
set -e
 
#cd /directory of scripts.. (put a variable in place if you wanna get crazy)
 
snmpwalk -v 2c -On -c 'xxxxxxxx' 172.16.1.1 .1.3.6.1.2.1.2.2.1.10.2 | cut -d " " -f 4 >> in
snmpwalk -v 2c -On -c 'xxxxxxxx' 172.16.1.2 .1.3.6.1.2.1.2.2.1.16.2 | cut -d " " -f 4 >> out
 
outrate_back=$(tail -n2 out | head -n1)
inrate_back=$(tail -n2 in | head -n1)
 
outrate=$(tail -n1 out)
inrate=$(tail -n1 in)
 
in_trans=$((($inrate-$inrate_back)/300))
out_trans=$((($outrate-$outrate_back)/300))
 
#since the Mbps number is multiplied first it should always be higher than .5
# therefore we don't need floats with bc as we can round to the next Mb
 
in_convert=$((($in_trans*8)/(1024*1024)))
out_convert=$((($out_trans*8)/(1024*1024)))
 
 
#change 14 to the matching Mbps value
if [ $in_convert -lt 14 ] ; then
        echo OK > /var/www/inbandcheck.html
else
        echo FAIL > /var/www/inbandcheck.html
fi
 
if [ $out_convert -lt 14 ] ; then
        echo OK > /var/www/outbandcheck.html
else
        echo FAIL > /var/www/outbandcheck.html
fi
 
#monitor okay with proper timing parameters to not have false positives for short spikes
exit 0