Simple DDOS Blocker

#! /bin/bash
while;;
    do
        for ip in `lsof -ni | grep httpd | grep -iv listen | awk '{print $8}' | cut -d : -f 2 | sort | uniq | sed s/"http->"//`;
    do
        noconns=`lsof -ni | grep $ip | wc -l`;
        echo $ip : $noconns;

        if [ "$noconns" -gt "20" ];
        then
            iptables -I INPUT -s $ip -p tcp -j REJECT --reject-with tcp-reset
        else
            fi;
    done
    sleep 60
done