How to make Double VPN within one server?

Question

linux

Good afternoon.
I have two IPs on VPS
On the first one VPN works and clients connect to it.
How can I make sure that the network connection is always from the second ip?
And at the same time, block access to clients if the second ip was suddenly disabled.
Thank you.

Answer 1

The most normal solution is a proxy for accessing the Internet. Otherwise, you need to come up with something with source based routing (ip rule) or vrf (ip nets)

Answer 2

When writing the NAT iptables rule for VPN users to access the Internet, you need to specify the output IP instead of the output interface