TsgcSTUNClient

TsgcSTUNClient is the client that implements the STUN protocol and allows you to send binding requests to STUN servers.

 

The component allows you to use UDP and TCP as transport. When using UDP as transport, it implements a Retransmission mechanism to re-send requests if the response has not arrived after a short time.

 

Basic usage

Usually STUN servers run on UDP port 3478 and don't require authentication, so in order to send a STUN request binding, fill the server properties to allow the client to know where to connect and Handle the events where the component will receive the response from server.

 

Configure the server

• Host: the IP or DNS name of the server, example: stun.sgcwebsockets.com
• Port: the listening Server port, example: 3478

 

Call the method SendRequest, to send a request binding to STUN server.

 

Handle the events

• If the server returns a successful response, the event OnSTUNResponseSuccess will be called and you can access the binding information by reading the aBinding object.

• If the server returns an error, the event OnSTUNResponseError will be called and you can access the Error Code and Reason reading the aError object.

 

    oSTUN := TsgcSTUNClient.Create(nil);
    oSTUN.Host := 'stun.sgcwebsockets.com';
    oSTUN.Port := 3478;
    oSTUN.SendRequest;

    procedure OnSTUNResponseSuccess(Sender: TObject; const aSocket: TsgcSocketConnection; 
      const aMessage: TsgcSTUN_Message; const aBinding: TsgcSTUN_ResponseBinding);
    begin
      DoLog('Remote IP: ' + aBinding.RemoteIP + '. Remote Port: ' + IntToStr(aBinding.RemotePort));
    end;

    procedure OnSTUNResponseError(Sender: TObject; const aSocket: TsgcSocketConnection; 
      const aMessage: TsgcSTUN_Message; const aError: TsgcSTUN_ResponseError);
    begin
      DoLog('Error: ' + IntToStr(aError.Code) + ' ' + aError.Reason);
    end;