Blitz Relay for Fish-Networking

A relay transport for Fish-Networking 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 2022.3 or later
• Fish-Networking

Installation

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

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

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

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

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 TransportManager component to the same GameObject.
3. Add a BlitzRelayTransport component to the same GameObject.
4. Assign the BlitzRelayTransport component to the TransportManager component's Transport field.

Configuration

Add the BlitzRelayTransport component to the same GameObject as your Fish-Networking NetworkManager. 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. For hosts, this is assigned by the relay after room creation and can be retrieved at runtime via GetRoomCode().
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.

Runtime API

Several methods are available for script-driven configuration after the transport has been initialised:

• SetRelayAddress(string) / GetRelayAddress() → Change or read the relay server address.
• SetRelayPort(ushort) / GetRelayPort() → Change or read the relay server port.
• SetRoomCode(string) / GetRoomCode() → Set or retrieve the current room code.
• SetRoomHostToken(string) / GetRoomHostToken() → Manage the host token assigned by the relay (used internally for room ownership).
• SetMaximumClients(int) / GetMaximumClients() → Adjust or read the client limit.
• IsRelayHostAvailable → Indicates whether the local player is, or can become, the relay host.
• OnRelayHostAvailabilityChanged → Event that fires when host availability changes (e.g. after a host migration).

License

MIT License. See LICENSE for details.

Copyright 2026 Abdelfattah Radwan