Blitz Relay for NGO

A relay transport for Netcode for GameObjects that routes all client traffic through a Blitz Relay server instance, removing the need for clients to have publicly reachable IP addresses or open ports. This makes it suitable for deployments where NAT traversal or firewall restrictions make direct peer-to-peer connections unreliable or impractical.

The transport uses a modified build of LiteNetLib internally for its UDP connections to the relay.

Requirements

• Unity 6000.0 or later
• Netcode for GameObjects

Installation

Open the Unity Package Manager (Window > Package Manager) and add the package via git URL:

https://github.com/abdelfattahradwan/blitz-relay-for-ngo.git?path=/Packages/com.winterboltgames.blitzrelayforngo

Or add the following entry to your project's Packages/manifest.json:

"com.winterboltgames.blitzrelayforngo": "https://github.com/abdelfattahradwan/blitz-relay-for-ngo.git?path=/Packages/com.winterboltgames.blitzrelayforngo"

Features

• Relay-based architecture: All game traffic flows through a relay server, so clients never need to expose their IP addresses or open firewall ports.
• Room-based: Hosts create rooms and receive a room code from the relay; clients join by supplying that room code.
• Basic Host migration: When the current host disconnects, the relay can promote an existing client to become the new host.

Setup

1. Add a GameObject with a NetworkManager component to your scene.
2. Add a BlitzRelayTransport component to the same GameObject.
3. Assign the BlitzRelayTransport component to NetworkManager.NetworkConfig.NetworkTransport.
4. For hosts, set the relay address, port, key, and maximum clients, then call NetworkManager.StartHost() or NetworkManager.StartServer().
5. For clients, set the relay address, port, key, and room code, then call NetworkManager.StartClient().

Configuration

The following fields are exposed in the Inspector:

Field	Type	Description
Relay Address	string	IP address or hostname of the relay server. Defaults to 127.0.0.1.
Relay Port	ushort	Port number the relay server is listening on. Defaults to 7770.
Relay Key	string	Connection key used to authenticate with the relay.
Room Code	string	Room code to join on the relay. Hosts receive this from the relay after room creation.
Do Not Route	bool	When enabled, packets are sent directly to the network interface without OS-level routing.
Maximum Clients	int	Maximum number of simultaneous client connections. Defaults to 4096.
Disconnect Timeout Milliseconds	int	LiteNetLib inactivity timeout. Defaults to 30000.

Runtime API

Several methods and events are available for script-driven configuration:

• SetRelayAddress(string) / GetRelayAddress() - Change or read the relay server address.
• SetRelayPort(ushort) / GetRelayPort() - Change or read the relay server port.
• SetRelayKey(string) / GetRelayKey() - Change or read the relay connection key.
• SetRoomCode(string) / GetRoomCode() - Set or retrieve the current room code.
• SetRoomHostToken(string) / GetRoomHostToken() - Manage the host token assigned by the relay.
• SetMaximumClients(int) / GetMaximumClients() - Adjust or read the client limit.
• IsRelayHostAvailable - Indicates whether the relay host is currently available.
• OnRelayHostAvailabilityChanged - Event that fires when host availability changes.
• HasPendingHostPromotion - Indicates whether this client has promotion data waiting to be claimed.
• ClearPendingHostPromotion() - Clears pending host promotion data.
• OnHostPromotionReceived - Event that fires when the relay promotes this client to host.

Host Promotion

When a client is promoted to host, the transport stores the claim data and raises OnHostPromotionReceived. NGO owns its own lifecycle, so your game code should shut down the current client session and start host mode. The next server start will claim the promoted room automatically.

License

MIT License. See LICENSE for details.

Copyright 2026 Abdelfattah Radwan