As we all know, IPv4 addresses are running out in the world (just pretend I'm talking nonsense if I'm wrong), so not all ISPs in China have public IP addresses. At the same time, there are many strange requirements (like wanting to play Command & Conquer remotely), and to achieve the effect of building a remote intranet, some special methods need to be used for networking. In fact, there are many articles about remote networking, such as Lemon Rain's article "Playing LAN Games Remotely - Building a Remote Server Network Quickly with N2N," which uses a software called N2N to establish tunnels. However, when I tried to use N2N for networking, I encountered several problems. First of all, I could only find a version of the Windows client v2 compiled by a network blogger, and it was very slow to download the client from a domestic server.
At one point, I didn't want to tinker anymore and thought about using ready-made LAN gaming platforms (like WANGYI), but after downloading and registering (this platform actually requires an ID card for registration, which is ridiculous, although I registered with a generated ID card number), it kept getting stuck at the loading screen when logging in. Helpless, I had to see if there were any other solutions.
Upon the suggestion of a friend who really wanted to play Red Alert 3, I researched ZeroTier, a solution for remote networking, and found it quite convenient.
But here's the problem: after I started using ZeroTier, the tunnels were established, but for some reason, two nodes couldn't ping each other.