How is it possible to restrict access to resources by IP?

Question

linux

The question is simple: how is it possible to differentiate access to resources by IP?
Preamble:
There is a network, there is an OpenVPN server and a bunch of virtual machines inside the network .. You need to give people access only to certain resources (virtual machines). At the same time, he should not see (or should not get) to resources (virtual computers) that do not concern him.

Answer 1

Allocate a network for openvpn clients. Rule the acl rules where to go, where not, on the border firewall.

Answer 2

For each user, assign an ip on the vpn server, in the iptables settings you prescribe the necessary rules for the user. Details: lithium.opennet.ru/articles/openvpn/openvpn-howto....