Site available via OpenVPN but not Wireguard over AirVPN

My current setup is pfSense Plus 23.09.01, with a vlan exiting all traffic via AirVPN. This works fine.

The vpn traffic exits via a gateway group, when that gateway group has openVPN servers I can reach the site, when it’s Wireguard servers the browser says the connection has timed out.

Further more, I use Firefox with Duck Duck Go as the search engine, this fails to resolve any websites over Wireguard (when I use Google no problem), over openVPN I don’t have any problems. Tried Brave browser, same result.

Again the only thing I have changed was the protocol.

Site: Oysta Technology
ISP: Virgin Media

Any insight ? I’m not even sure how to troubleshoot this, nothing in the pfSense logs jumps out at me.

I would guess that the public IP you are assigned is different and possibly blocked by the site.

Yeah I though it might that too, setup both openVPN and wireguard clients from the same servers. No issues with openVPN, wireguard failed.

Strangely, Linux Mint homepage is actively blocked on wireguard but not on openvpn.

Duck Duck Go homepage just times out over wireguard.

Only just setup wireguard recently, but I haven’t seen any “usual” sites block connections via openVPN.

My only thought is that wireguard traffic looks different to openvpn traffic, and this is what’s triggering site to block or timeout the connection.

Managed to get to the bottom of this, setting the MTU and MSS on the Wireguard interface fixed this. Site was then accessible when set.

Evidently fragmentation and data packets not all treated the same, need to read up on this area a bit more.