IPtables Configuration

 $IPTABLES -F INPUT
 $IPTABLES -P OUTPUT DROP
 $IPTABLES -F OUTPUT
 $IPTABLES -P FORWARD DROP
 $IPTABLES -F FORWARD
 $IPTABLES -F -t nat
 #Not needed and it will only load the unneeded kernel module
 #$IPTABLES -F -t mangle

 # Flush the user chain.. if it exists
 if [ -n "`$IPTABLES -L | $GREP drop-and-log-it`" ]; then
 $IPTABLES -F drop-and-log-it
 fi

 # Delete all User-specified chains
 $IPTABLES -X

 # Reset all IPTABLES counters
 $IPTABLES -Z

 #Configuring specific CHAINS for later use in the ruleset
 #
 # NOTE: Without the --log-level set to "info", every single
 # firewall hit will goto ALL vtys. This is a very big
 # pain.

 echo " Creating a DROP chain.."
 $IPTABLES -N drop-and-log-it
 $IPTABLES -A drop-and-log-it -j LOG --log-level info
 $IPTABLES -A drop-and-log-it -j DROP
 echo -e "\n - Loading INPUT rulesets"

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 # INPUT: Incoming traffic from various interfaces. All rulesets are
 # already flushed and set to a default policy of DROP.