A friend and I want to play Portal Co-Op (which allows for using IP address to connect directly player). He only has access to 4G however, and does not have access to wired broadband. Needless to say, he has really bad latency and connection issues. I have set up a cloud server on DigitalOcean, and we both can SSH into it, with very little latency. Can we just create a VPN on this server, and connect to each other via the VPN? Is there a better solution?
Happy cake day! 
Also, if you both connect to the server via VPN, and then use the “local” IP addresses for that PN, it would work effectively like you were on a LAN (with higher pings)
Your ping to each other would be roughly equivalent to the Ping you guys get right now added together.
Try zerotier. It works like a vpn but uses udp-hole punshing to connect the clients directly to each other. (No additional latency. They even have a free tier.
torrent can determine your location by checking your IP address. only use residential ip will not be detected. recommend widevpn, support wireguard, unblock any content. $9.99/yearly
Thanks for the wish! I didn’t even realise lol
Could you specify how exactly would we connect to the server via VPN? Do I need to setup OpenVPN Access on the server? I’m somewhat of a noob when it comes to networking.
Thanks for the suggestion! This is exactly what I needed. Will save me a bunch of time and effort.
You set up OPENVPN (There’s tons of resources on how to set this up. Just make sure you use reasonable security settings because some of them are a little outdated) Also make sure to set up different accounts for you and your friend.
You connect. The VPN will then assign you an IP address (usually in the 10.x.x.x range)
Let’s say you get given the IP 10.0.1.5, your friend would connect and use that IP to connect to your portal server.
Thanks a lot! This was really helpful 