DTLSServer | Godot Docs 4.3

This class is used to store the state of a DTLS server. Upon setup it converts connected PacketPeerUDP to PacketPeerDTLS accepting them via take_connection as DTLS clients. Under the hood, this class is used to store the DTLS state and cookies of the server. The reason of why the state and cookies are needed is outside of the scope of this documentation.

Below a small example of how to use it:

# server_node.gd
extends Node

var dtls := DTLSServer.new()
var server := UDPServer.new()
var peers = []

func _ready():
    server.listen(4242)
    var key = load("key.key") # Your private key.
    var cert = load("cert.crt") # Your X509 certificate.
    dtls.setup(key, cert)

func _process(delta):
    while server.is_connection_available():
        var peer: PacketPeerUDP = server.take_connection()
        var dtls_peer: PacketPeerDTLS = dtls.take_connection(peer)
        if dtls_peer.get_status() != PacketPeerDTLS.STATUS_HANDSHAKING:
            continue # It is normal that 50% of the connections fails due to cookie exchange.
        print("Peer connected!")
        peers.append(dtls_peer)

    for p in peers:
        p.poll() # Must poll to update the state.
        if p.get_status() == PacketPeerDTLS.STATUS_CONNECTED:
            while p.get_available_packet_count() > 0:
                print("Received message from client: %s" % p.get_packet().get_string_from_utf8())
                p.put_packet("Hello DTLS client".to_utf8_buffer())

# client_node.gd
extends Node

var dtls := PacketPeerDTLS.new()
var udp := PacketPeerUDP.new()
var connected = false

func _ready():
    udp.connect_to_host("127.0.0.1", 4242)
    dtls.connect_to_peer(udp, false) # Use true in production for certificate validation!

func _process(delta):
    dtls.poll()
    if dtls.get_status() == PacketPeerDTLS.STATUS_CONNECTED:
        if !connected:
            # Try to contact server
            dtls.put_packet("The answer is... 42!".to_utf8_buffer())
        while dtls.get_available_packet_count() > 0:
            print("Connected: %s" % dtls.get_packet().get_string_from_utf8())
            connected = true