#!/bin/bash
IPT=$(which iptables) 
NET="0/0" 
FW="192.0.2.1" 
WAN1="203.0.113.1" 
WAN2="198.51.100.1"
  
ping () 
 { 

$IPT -A INPUT -p icmp --icmp-type 0  -s $NET -d $FW -j ACCEPT 
$IPT -A OUTPUT -p icmp --icmp-type 8 -s $FW -d $NET -j ACCEPT

$IPT -A INPUT -p icmp --icmp-type 0  -s $NET -d $WAN1 -j ACCEPT 
$IPT -A OUTPUT -p icmp --icmp-type 8 -s $WAN1 -d $NET -j ACCEPT

$IPT -A INPUT -p icmp --icmp-type 0  -s $NET -d $WAN2 -j ACCEPT 
$IPT -A OUTPUT -p icmp --icmp-type 8 -s $WAN2 -d $NET -j ACCEPT
 } 
ping