The purpose of this article is to realize the local machine X can communicate over local router A running pfSense through the WAN gateway of the remote router B also with pfSense.
The lab environment
Local machine X: [IP_ADDR]=192.168.0.254 [Mask]=255.255.255.0 [GW]=192.168.0.1 Local router A: [IP_ADDR]=192.168.0.1 [Mask]=255.255.255.0 [GW]=Router_A_WAN_ADDR Remote router B: [IP_ADDR]=192.168.11.1 [Mask]=255.255.255.0 [GW]=Router_B_WAN_ADDR OpenVPN client on router A: [Mode]=TUN [Interface]=OVPN_A [IPv4 Tunnel Network]=192.168.30.49/30 OpenVPN server on router B: [Mode]=TUN [Interface]=OVPN_B [IPv4 Tunnel Network]=192.168.30.50/30
1. Establish an OpenVPN TUN tunnel between router A and B anyway. This is not the focus of this article.
2. Set a allow all rule for OVPN_B on router B
3. Set an Outbound NAT on the firewall of router B
4. Set a rule for routing traffic to OVPN_A on the LAN firewall table of router A
Result: (Tested on local machine X)
> tracert 192.168.11.1 Tracing route to 192.168.11.1 over a maximum of 30 hops 1 20 ms 20 ms 20 ms 192.168.30.49 2 30 ms 30 ms 30 ms 192.168.11.1 Trace complete.