Routing / IPTables question
I'm having trouble trying to understand iptables and linux routes.
I've gotten as far as doing iptables port forwards and routing specific ips to another network.
Say I have LAN A (192.168.1.0/24), one of the clients in this LAN has openvpn connection to an external server (192.168.100.0/24). Say the external client is currently connected as 192.168.100.2, and the LAN A client who's connected to openvpn is 192.168.100.1
I want other clients in 192.168.1.0/24 to be able to connect to 192.168.100.2 by ip, how do I do this? I routed 192.168.1.0 to 192.168.100.1, but I'm not sure where to go from there. Traceroute of 192.168.100.2 from other clients in LAN A shows it does get routed to 192.168.100.1 but does not get a response. What should I be doing on 192.168.100.1?