nagios-port-monitoring.sh

#!/bin/bash

# Command Structure for use this script,
# Command:
# ./nagios-port-monitoring.sh -p 5999 -w 3 -c 5
# Result:
# CRITICAL- 0 Established connection on PORT 5999 | 'Usage'=0;3;5;0;10

# Status Code
# STATE_OK=0
# STATE_WARNING=1
# STATE_CRITICAL=2
# STATE_UNKNOWN=3
# STATE_DEPENDENT=4

help() {
cat << END
Usage :
        check_port_monitoring.sh -p [Port] -w [VALUE] -c [VALUE]

        OPTION          DESCRIPTION
        ----------------------------------
        -h              Help
        -w [VALUE]      Warning Threshold
        -c [VALUE]      Critical Threshold
        -p [Path]       Port Number
        ----------------------------------
Note : [VALUE] must be an integer.
END
}

while getopts "p:w:c:" opt
do
   case "$opt" in
      p ) PORT="$OPTARG" ;;
          w ) WARN="$OPTARG" ;;
      c ) CRIT="$OPTARG" ;;
      *) help ;;
   esac
done

# Print helpFunction in case parameters are empty
if [ -z "$PORT" ]
then
   echo "Some or all of the parameters are empty";
   help
fi


# Warning threshold must be less than Critical threshold
if [ $WARN -ge $CRIT ]
then
        echo "ERROR : Warning threshold must be less than Critical threshold."
        exit 3
fi

# Command
result=`netstat -pant | grep :$PORT |  egrep -c 'LISTEN|ESTABLISHED'`
OUTPUT=`echo $result Established connection on PORT $PORT`
WARN_LIMIT_FOR_OK=$(($WARN-1))
# echo $WARN_LIMIT_FOR_OK
CRITICAL_LIMIT_FOR_WARN=$(($CRIT-1))
# echo $CRITICAL_LIMIT_FOR_WARN 


if [[ $result -ge 1 && $result -le $WARN_LIMIT_FOR_OK  ]]
then
                STATUS="OK";
        EXITSTAT=0;
elif [[ $result -ge $WARN && $result -le $CRITICAL_LIMIT_FOR_WARN ]]
then
        STATUS="WARNING";
        EXITSTAT=1;

elif [[ $result -ge $CRIT ]]
then
        STATUS="CRITICAL";
        EXITSTAT=2;

else
       if [ $result -le 0 ]
       then
               STATUS="CRITICAL";
               EXITSTAT=2;
       fi
fi

# Summary Data
# echo "'Usage'=${result};$WARN;$CRIT;0;100" && exit $STATE_OK
# echo "'Usage'=$STATUS- $OUTPUT;$WARN;$CRIT;0;100" && exit $STATE_OK

echo "$STATUS- $OUTPUT | 'Usage'=${result};$WARN;$CRIT;0;100" && exit $EXITSTAT