OpenVPN TAP server for "local" gaming

[Zeranoe]

I'm trying to set up an OpenVPN server on my pfSense router so that I can have myself and others play CIV in a "local" game.

I have the server set up and functioning, it's accepting connections and I'm able to have some remote clients VPN to it. The issue is that CIV isn't seeing the other clients when you try to search for local games.

I did a Wireshark capture while it was scanning and I see a bunch of UDP requests from the local IP to 255.255.255.255.

To make sure everything was on the same subnet I also connect to the pfSense VPN from my local machine which is within the LAN. I wasn't sure if this would work but I get an IP 10.0.1.3 while the remote client is 10.0.1.2.

I'm able to ping the other machine fine, but for whatever reason the two machines will not connect in-game.

I've heard that this issue goes away if you host the OpenVPN server in TAP mode from the actual local client and have the remote ones connect that way, but I'm not entirely sure why.

Any ideas would be great, and before anyone asks these are all legitimate copies of the game purchased on Steam, it's just that CIV 5 is literally unplayable over the internet and disconnects all of the time.

[Zeranoe]

Some further digging and this seems to be a metric issue.

If I change the metric for the TAP adapter on both clients they can find each other and everything works, but not otherwise.

Is there a way to have Windows push all of the broadcast traffic down the VPN without having to manually change the adapter metric setting? Perhaps some setting I can push though the OpenVPN server that ensures 255.255.255.255 requests go down the VPN?