Connect() does not use tls 1.2 by default for SslStream

[rdub1a4]

Would be nice for Connect() to use tls 1.2 by default or allow for SslProtocols to be passed to sslStream.AuthenticateAsClient().

Workaround is to create SslStream manually and pass to Pop3Client.Connect(Stream):

/// <summary>
        /// Need to manually create Pop3Client.Connect TcpStream to force tls1.2 to be used since not on .net 4.6 yet 
        /// </summary>
        /// <param name="client"></param>
        /// <param name="host"></param>
        /// <param name="port"></param>
        /// <param name="useSsl"></param>
        private void OpenPopConnect(Pop3Client client, string host, int port, bool useSsl, int receiveTimeout, int sendTimeout, RemoteCertificateValidationCallback certificateValidator)
        {
            TcpClient clientSocket = new TcpClient();
            clientSocket.ReceiveTimeout = receiveTimeout;
            clientSocket.SendTimeout = sendTimeout;

            try
            {
                clientSocket.Connect(host, port);
            }
            catch (SocketException e)
            {
                // Close the socket - we are not connected, so no need to close stream underneath
                clientSocket.Close();

                throw new PopServerNotFoundException("Server not found", e);
            }

            Stream stream;
            if (useSsl)
            {
                // If we want to use SSL, open a new SSLStream on top of the open TCP stream.
                // We also want to close the TCP stream when the SSL stream is closed
                // If a validator was passed to us, use it.
                SslStream sslStream;
                if (certificateValidator == null)
                {
                    sslStream = new SslStream(clientSocket.GetStream(), false);
                }
                else
                {
                    sslStream = new SslStream(clientSocket.GetStream(), false, certificateValidator);
                }
                sslStream.ReadTimeout = receiveTimeout;
                sslStream.WriteTimeout = sendTimeout;

                // Authenticate the server
                sslStream.AuthenticateAsClient(host, null, System.Security.Authentication.SslProtocols.Tls12, true);

                stream = sslStream;
            }
            else
            {
                // If we do not want to use SSL, use plain TCP
                stream = clientSocket.GetStream();
            }

            // Now do the connect with the same stream being used to read and write to
            client.Connect(stream);
        }

[wriedmann]

Thank you very much! Your comment helped me to solve issues - Italian PEC requires at least TLS 1.2, and thanks to your comment I was able to make it work.