Script to redirect port on host to diffetent ip

redirect_port_to_ip-port.sh

#!/bin/bash


function printHelp(){
        echo "This tool can be used to redirect tcp port from host on which is being run to another routable ip and port from this host"
        echo
        echo "USAGE:"
        echo "$(basename $0) <destinationIP> <sourcePort> <destinationPort>"
}


function applyRules(){

        iptables -A POSTROUTING -j MASQUERADE
        iptables -A PREROUTING -p tcp --dport $2 -j DNAT --to-destination $1:$3 -o eth0
        iptables -A FORWARD -d $1 -p tcp --dport $3 -j ACCEPT
        iptables -A FORWARD -s $1 -p tcp --sport $3 -j ACCEPT

}

function main(){
        if [ $# -ne 3 ]; then
                echo "ERROR: Not enough arguments given"
                printHelp
                exit 1
        fi
        applyRules $@
}

main $@