How to Setup A Network Router

Set up the internal connection within linux first

Using nmcli command line steps

Step 1. Verify which interface : ip a

Step 2. Assign Ipv4: nmcli con mod enp0s3 ipv4.addresses 192.168.10.1/24

Step 3. Assign gateway: nmcli con mod enp0s3 ipv4.gateway 192.168.10.1

Step 4. Configure dhcp to static: nmcli con mod enp0s3 ipv4.method manual

Step 5. Set DNS value: nmcli con mod enp0s3 ipv4.dns "8.8.8.8" (Only configure once DNS is up)

Step 6. Reload interface: nmcli con up enp0s3

Step 7. Verify configurations: cat /etc/sysconfig/network-scripts/ifcfg-enp0s3

Once successfully configured, the output should be as followed seen in the picture above

Now we will move on to the part of configuration to allow other device within the same network to connect to the internet through network router

Step 1. enable IP forwarding

sysctl -w net.ipv4.ip_forward=1

Step 2. Start and run firewall daemon

systemctl is-active firewalld

systemctl is-enabled firewalld

systemctl enable firewalld

systemctl start firewalld

Step 3. After enabling the firewall daemon, enable masquerade for the public zone

firewall-cmd --permanent --zone=public --add-masquerade

firewall-cmd --reload

Step 4. Once the above steps are all finish , attempt to ping 8.8.8.8 from the other device