If you want to configure NAT to share the internet access to the other clients on the network that share the same private network

1. Edit the following file

vi /etc/sysctl.conf

2. change the line

from

net.ipv4.ip_forward = 0

to

net.ipv4.ip_forward = 1

3. Now set the gateway IP of all the local clients to NAT server IP.

If required, please restart the network service or reboot the server.