scanner.sh

#!/bin/bash

# your ip address
ip_address="192.168.15.142"

function change_dns() {
    route add default gw 192.168.14.200
    echo "nameserver 80.191.216.2" > /etc/resolv.conf
    echo "nameserver 8.8.8.8" >> /etc/resolv.conf
    echo "nameserver 4.2.2.4" >> /etc/resolv.conf
}

function change_ip() {
    ip addr del $1/23 dev enp3s0
    ip addr add $2/23 dev enp3s0    
}

function check_internet() {
    ping -c 1 gstatic.com 1> /dev/null 2>&1    
    result=$?
    return $result
}

old_target=$ip_address

echo "~ checking nodes in network ..."
targets=$(nmap -sP 192.168.14.0/23 | grep -Po "([0-9]{1,3}[\.]){3}[0-9]{1,3}")
echo "~ checking intenet access for each nodes ..."
for target in $targets; do
    if [[ $target == "192.168.14.200" ]]; then
        continue
    fi
    change_ip $old_target $target 
    change_dns
    sleep 1

    check_internet
    if [[ $? -eq 0 ]]; then
        echo "$target"
    fi
    
    old_target=$target
done

echo "~ removing old ip address ..."
change_ip $old_target $ip_address 
change_dns
sleep 1
echo "~ smile and have fun !"