Hi @vivek1978,

I’ll recommend reading the following documentation on DigitalOcean about it - https://www.digitalocean.com/docs/networking/private-networking/how-to/enable/

Here is a part for Ubuntu -

When you enable private networking after the Droplet is created, you need to manually configure the private networking on the Droplet itself. How you do this depends on which Linux distribution your Droplet is running.

On Ubuntu 18.04, you need to use Netplan to define the network interface using the Droplet’s private IP address and the MAC address for the Ethernet interface.

To get the MAC address, use lshw to list the details of your server’s network-class hardware.

lshw -class network

To fully grasp how to configure it, I’ll urge you to read the documentation.

Regards,
KDSys