Creating network connections with Godot is simple — as long as you have the other party’s IP address, and there’s no NAT gateway involved. Unfortunately, that’s exactly the problem in most cases. You don’t know the other party’s IP, and these days, just about everyone is behind a combination wifi router/gateway/firewall with NAT.
Conceptually, NAT hole-punching is pretty simple, and this video explains how it’s done with just netcat.
In a nutshell:
listen on a particular port (e.g. 50001)
nc -u -l 50001
echo ‘hello’ | nc -u ipaddr 50001
echo ‘hole punch’ | nc -u -p 50001 ipaddr 50002
third party exchanges ip addresses
Putting it all together, player A (hosting a game) would require the game to connect to the directory server.
The directory server would list the game as something a player can now connect to.
player B (client who wants to join) will tell the directory service that it wants to connect, and will send its info
The directory server forwards the information to player A (host), player A will then send a packet to player B, and respond to the directory server
The directory server will then tell player B to go ahead and connect to player A.
Player B should be able to punch through to player A
With Godot, the connections from client to host would use ENetMultiplayerPeer.create_client(), which can specify the local port.
Development snapshot #4 of Godot Engine 4.1 is here. Among many other changes, it fixes a lighting issue related to using Light-only mode in CanvasItemMaterial (#44559). Unfortunately, it also introduced a UX issue with gradient color pickers (#77745), which makes it quite difficult to work with gradients at all. If you use gradients, I recommend …
A new version of the Inventory System is available with more multiplayer-related features. The Multiplayer Interaction Demo can now run in multiple modes, through two separate implementations of the Character scene: The simple character scene leverages the MultiplayerSynchronizer and can either let the client have authority and move the character, or have the client send …
Any sufficiently large code base needs documentation. Documentation tends to come in all sorts of shapes and sizes. Among them are high-level architecture and design docs, class and method interface documentation, and inline comments to explain optimized or complex algorithms so the reader doesn’t have to parse the logic in their head (often, this is …
The latest inventory system is now available and it focuses on multiplayer permissions. The new Access Manager component validates client requests to ensure players can’t cheat and interact with inventories they’re not supposed to be able to have access to. New features: Bug fixes:
Creating a UDP peer-to-peer connection
Creating network connections with Godot is simple — as long as you have the other party’s IP address, and there’s no NAT gateway involved. Unfortunately, that’s exactly the problem in most cases. You don’t know the other party’s IP, and these days, just about everyone is behind a combination wifi router/gateway/firewall with NAT.
Conceptually, NAT hole-punching is pretty simple, and this video explains how it’s done with just netcat.
In a nutshell:
Putting it all together, player A (hosting a game) would require the game to connect to the directory server.
With Godot, the connections from client to host would use ENetMultiplayerPeer.create_client(), which can specify the local port.
Here’s an older example of a signaling server: https://github.com/Faless/gd-webrtc-signalling/tree/master
Related Posts
Godot Engine 4.1.dev4 is available
Development snapshot #4 of Godot Engine 4.1 is here. Among many other changes, it fixes a lighting issue related to using Light-only mode in CanvasItemMaterial (#44559). Unfortunately, it also introduced a UX issue with gradient color pickers (#77745), which makes it quite difficult to work with gradients at all. If you use gradients, I recommend …
Inventory System v1.14 available
A new version of the Inventory System is available with more multiplayer-related features. The Multiplayer Interaction Demo can now run in multiple modes, through two separate implementations of the Character scene: The simple character scene leverages the MultiplayerSynchronizer and can either let the client have authority and move the character, or have the client send …
Generating documentation for GDScript
Any sufficiently large code base needs documentation. Documentation tends to come in all sorts of shapes and sizes. Among them are high-level architecture and design docs, class and method interface documentation, and inline comments to explain optimized or complex algorithms so the reader doesn’t have to parse the logic in their head (often, this is …
Inventory System v1.11 available
The latest inventory system is now available and it focuses on multiplayer permissions. The new Access Manager component validates client requests to ensure players can’t cheat and interact with inventories they’re not supposed to be able to have access to. New features: Bug fixes: