Disable outgoing / incoming traffic on Ubuntu

Problem

User wants to disable internet access and only leave local network for Ubuntu (or any other linux system)

Solution

disable the internet using route del command

IP=$(/sbin/ip route | awk ‘/default/ { print $3 }’)
sudo /sbin/route del default gw “$IP”
echo “$IP” >~/tmp/gw.txt

file will be saved to /tmp/gw.txt to restore the internet connection

cat /tmp/gw.txt
route add default gw <IP address> <NETWORK INTERFACE>

Note:

Please change back to Apostrophes and backticks this is forum issue or using the attached script

Attachment: del_gw.sh

Another option if route del is not possible ( for example ansible fails if no route on some playbooks )

add route to your default network

route add default gw <YOUR IP ADDR> <INTERFACE>

route add default gw 10.50.77.210 ens192