Shell Programming and Scripting

#!/bin/sh
#begin routine for refused connections
#del existing block rule
if ipfw show | awk '{print $1}' | grep -q 350 ; then
        ipfw delete 350
fi
#5 or more refused connections
awk '/refused/  {try[$(NF)]++}
END {for (h in try) if (try[h] > 5) print h}' /var/log/sshd.log |sed 's/[()]//g'|
while read ip
do
echo 'adding' $ip        
ipfw -q add 350 deny tcp from $ip to any in
done
#
#begin routine for invalid users
if ipfw show | awk '{print $1}' | grep -q 360 ; then
        ipfw delete 360
fi
awk '/Invalid user/ {try[$(NF)]++}
END {for (h in try) if (try[h] > 5) print h}' /var/log/sshd.log |
while read ip
do
echo 'adding' $ip        
ipfw -q add 360 deny tcp from $ip to any in
done

#!/bin/sh
#begin routine for refused connections
#del existing block rule
if ipfw show | awk '{print $1}' | grep -q 350 ; then
        ipfw delete 350
fi
#First with 5 or more refused/Invalid user connections
awk '/refused/&&++try[$NF]>5{gsub(/[)(]/,"",$NF); print $NF; exit}' /var/log/sshd.log |
while read ip
do
    echo 'adding' $ip        
    ipfw -q add 350 deny tcp from $ip to any in
done
#
#begin routine for invalid users
if ipfw show | awk '{print $1}' | grep -q 360 ; then
        ipfw delete 360
fi
awk '/Invalid user/&&++try[$NF]>5{gsub(/[)(]/,"",$NF); print $NF; exit}' /var/log/sshd.log |
while read ip
do
    echo 'adding' $ip        
    ipfw -q add 360 deny tcp from $ip to any in
done