UDP

UDP does not work on a web build To work in editor in Windows, open Defender and sort by name to check all unity configs.

Use this to share data in a local network. You can find local clients with broadcast and retrieves the local address to start a server, share data between a pc and a smartphone connected on the same wifi...

This is more simple than Tcp connection: no networks, no dialogs, no responses.

For simple address sharing and nearby player, see Simple LocalNetwork

Simple UDP

Provides a very simple API to use UDP (but it is not a real connection).

// listen buffer or string
var mylistener = SimpleUdp.Listen(9580 /* port */, (byte[] buffer, IPEndPoint remote) => { }, /* IPAddress = Any */);
var mylistener = SimpleUdp.ListenString(9580 /* port */, (string msg, IPEndPoint remote) => { }, /* IPAddress = Any */);

// send data
await SimpleUdp.Send(stringOrBytes, "localhost", 9581 /* port */);

Server

UdpServer _server;

void Start() {
    _server = new UdpServer("unique key", /* broadcastPort = 9565, msgPort = 9566, timeout = 2f */);
    _server.OnConnected += OnPeerConnected;
    _server.OnDisconnected += OnPeerDisconnected;
    _server.Start();
}

void OnPeerConnected(UdpPeer peer) {
    Debug.Log("New connection " + peer.EndPoint.Address.ToString());

    peer.AddHandler(1, packet => {
        var pos = packet.Read<Vector3>();
        transform.localPosition = pos + new Vector3(1f, 0f, 0f);
        peer.Send(4, "Your Address is "+peer.EndPoint.Address);
    });
}

Client

UdpClient _client;

void Start() {
    _client = new UdpClient("unique key", /* broadcastPort = 9565, msgPort = 9566, timeout = 2f */);
    
    _client.OnConnected += () => Debug.Log("Connected to server : " + _client.ServerAddress);

    client.AddHandler(4 /* message ID */, packet => {
        Debug.LogError("Message from server: "+packet.Read<string>());
    });

    _client.Start();

    StartCoroutine(UpdatePositionRoutine());
}

IEnumerator UpdatePositionRoutine() {
    while (!_client.IsConnected) {
        yield return new WaitForSeconds(0.4f);
    }

    while (_client.IsConnected) {
        _client.Send(1 /* message ID */, transform.localPosition);
        yield return new WaitForSeconds(0.1f);
    }
}