Private Shared Sub ProcessClient(client As TcpClient)
    ' A client has connected. Create the 
    ' SslStream using the client's network stream.
    Dim sslStream = New SslStream(client.GetStream(), False)

    Try

        sslStream.AuthenticateAsServer(serverCertificate, clientCertificateRequired:=False, checkCertificateRevocation:=True)
        ' Display the properties And settings for the authenticated stream.
        DisplaySecurityLevel(sslStream)
        DisplaySecurityServices(sslStream)
        DisplayCertificateInformation(sslStream)
        DisplayStreamProperties(sslStream)

        ' Set timeouts for the read and write to 5 seconds.
        sslStream.ReadTimeout = 5000
        sslStream.WriteTimeout = 5000

        ' Read a message from the client.   
        Console.WriteLine("Waiting for client message...")
        Dim messageData As String = ReadMessage(sslStream)
        Console.WriteLine("Received: {0}", messageData)

        ' Write a message to the client.
        Dim message As Byte() = Encoding.UTF8.GetBytes("Hello from the server.<EOF>")
        Console.WriteLine("Sending hello message.")
        sslStream.Write(message)
    Catch e As AuthenticationException
        Console.WriteLine("Exception: {0}", e.Message)

        If e.InnerException IsNot Nothing Then
            Console.WriteLine("Inner exception: {0}", e.InnerException.Message)
        End If

        Console.WriteLine("Authentication failed - closing the connection.")
        sslStream.Close()
        client.Close()
        Return
    Finally
        ' The client stream will be closed with the sslStream
        ' because we specified this behavior when creating
        ' the sslStream.
        sslStream.Close()
        client.Close()
    End Try
End Sub

' Create a TCP/IP client socket.
' machineName is the host running the server application.
Dim client = New TcpClient(machineName, 443)
Console.WriteLine("Client connected.")

' Create an SSL stream that will close the client's stream.
Dim sslStream = New SslStream(
    client.GetStream(), False, 
    New RemoteCertificateValidationCallback(AddressOf ValidateServerCertificate), Nothing)

' The server name must match the name on the server certificate.
Try
    sslStream.AuthenticateAsClient(serverName)
Catch e As AuthenticationException
    Console.WriteLine("Exception: {0}", e.Message)

    If e.InnerException IsNot Nothing Then
        Console.WriteLine("Inner exception: {0}", e.InnerException.Message)
    End If

    Console.WriteLine("Authentication failed - closing the connection.")
    client.Close()
    Return
End Try

' Server name must match the host name and the name on the host's certificate. 
serverName = args(0)
' Create a TCP/IP client socket.
Dim client As New TcpClient(serverName, 80)
Console.WriteLine("Client connected.")
' Create an SSL stream that will close the client's stream.
Dim sslStream As New SslStream(
    client.GetStream(), False, 
    New RemoteCertificateValidationCallback(AddressOf ValidateServerCertificate), 
    New LocalCertificateSelectionCallback(AddressOf SelectLocalCertificate))