How to allow access to a specific IP address only for a specific network?

Question

openvpn

Good day to all!
There is a linux server with OpenVPN, it is also a gateway for networks 192.168.2.0/24, 192.168.4.0/24, 192.168.10.0/24 and a few more.
Each network on the server on a separate interface. OpenVPN clients connect to the server and crawl across all networks. This is how it should be and it works great.
But now the moment has come when one single client needs to be given VPN access to only ONE network (192.168.4.0/24). The client receives an IP address from the network 10.8.0.0/24, specifically 10.8.0.115.
How can I disable this IP from all networks except 192.168.4.0/24 using iptables?

Answer 1

iptables -I FORWARD -s 10.8.0.115/32 ! -d 192.168.4.0/24 -j DROP