Workout and count which hosts are connecting on the cassandra native port

nativeReport.sh

#!/bin/bash
# Scipt to count connected hosts on port, preform nslookup of hosts and output details
#
HOSTNAME=`hostname`

PORT=$1

IP_HOSTS_COUNT=`netstat -tn | 'next unless(/^tcp\s+\d+\s+\d+\s+\S+?:${PORT}\s+(\S+)?:/); print "$1\n";' | sort | uniq -c | awk '{print "tohost\t",$1,"\t"$2,"\tfromhost\n"}'`

while read -r line; do
        toline="${line/tohost/$HOSTNAME}"
        from_ip=`echo ${toline} | awk '{print $3}'`
        from_host=`nslookup ${from_ip} | grep 'name =' | awk '{print $4}'`
        if [ -z "$from_host" ]; then
                from_host="unknown"
        fi
        fromline="${line/fromhost/$from_host}"
        echo $fromline
done <<< "$IP_HOSTS_COUNT"