How to add a new gateway to an existing network card to access virtual box?

Question

I have a ubuntu 16.04 running on a remote server, for which I have a fixed address assigned by the provider. On this machine I have a virtual box virtual server running with a static address of 192.168.0.104

How do I add a gateway to access this address. it needs to be accessible only on the remote server. not from the internet.

Answer 1

In general though you don't need to give it a gateway, you just need to be part of the same subnet.

In general in a running system you can simply do:

ip addr add 192.168.0.1/24 dev

In general you can also simply add addresses to your main internet device, whatever it is.

You don't actually need any "routing" the kernel will know to send packages for a certain IP out a certain device. It doesn't require any gateways; adding yourself to that subnet would automatically set up the required routes.

To make it persistent depends on what network solution you are using, I can't comment on that.

Answer 2

1. NATing should be enabled for interface which is towards internet at server and other interface should acts as gateway 192.168.0.1 towards local machines or VMs.
2. Remote client if want to access 192.168.0.x which is private network of server then it has to add route in client machine such as
   route add -net 192.168.0.1 default gateway netmask 255.255.0.0 dev

Then ping the 192.168.0.x from client.