HttpListener.UnsafeConnectionNtlmAuthentication Property

Definition

Gets or sets a Boolean value that controls whether, when NTLM is used, additional requests using the same Transmission Control Protocol (TCP) connection are required to authenticate.

public:
 property bool UnsafeConnectionNtlmAuthentication { bool get(); void set(bool value); };
public bool UnsafeConnectionNtlmAuthentication { get; set; }
member this.UnsafeConnectionNtlmAuthentication : bool with get, set
Public Property UnsafeConnectionNtlmAuthentication As Boolean

Property Value

Boolean

true if the IIdentity of the first request will be used for subsequent requests on the same connection; otherwise, false. The default value is false.

Exceptions

This object has been closed.

Examples

The following code example demonstrates setting this property.

public static void SimpleListenerWithUnsafeAuthentication(string[] prefixes)
{
    // URI prefixes are required,
    // for example "http://contoso.com:8080/index/".
    if (prefixes == null || prefixes.Length == 0)
      throw new ArgumentException("prefixes");
    // Set up a listener.
    HttpListener listener = new HttpListener();
    foreach (string s in prefixes)
    {
        listener.Prefixes.Add(s);
    }
    listener.Start();
    // Specify Negotiate as the authentication scheme.
    listener.AuthenticationSchemes = AuthenticationSchemes.Negotiate;
    // If NTLM is used, we will allow multiple requests on the same
    // connection to use the authentication information of first request.
    // This improves performance but does reduce the security of your
    // application.
    listener.UnsafeConnectionNtlmAuthentication = true;
    // This listener does not want to receive exceptions
    // that occur when sending the response to the client.
    listener.IgnoreWriteExceptions = true;
    Console.WriteLine("Listening...");
    // ... process requests here.

    listener.Close();
}
Public Shared Sub SimpleListenerWithUnsafeAuthentication(ByVal prefixes As String())
    ' URI prefixes are required,
    ' for example "http://contoso.com:8080/index/".
    If prefixes Is Nothing OrElse prefixes.Length = 0 Then Throw New ArgumentException("prefixes")
    ' Set up a listener.
    Dim listener As HttpListener = New HttpListener()

    For Each s As String In prefixes
        listener.Prefixes.Add(s)
    Next

    listener.Start()
    ' Specify Negotiate as the authentication scheme.
    listener.AuthenticationSchemes = AuthenticationSchemes.Negotiate
    ' If NTLM Is used, we will allow multiple requests on the same
    ' connection to use the authentication information of first request.
    ' This improves performance but does reduce the security of your 
    ' application. 
    listener.UnsafeConnectionNtlmAuthentication = True
    ' This listener does Not want to receive exceptions 
    ' that occur when sending the response to the client.
    listener.IgnoreWriteExceptions = True
    Console.WriteLine("Listening...")
    ' ... process requests here.

    listener.Close()
End Sub

Remarks

When this property is set to true and the first request over a particular TCP connection is authenticated using NTLM, subsequent requests over the same TCP connection are processed using the authentication information (IIdentity) of the initial request.

This property has no effect when NTLM is not the authentication protocol. When Negotiate is specified as the authentication protocol, this property has an effect only if NTLM is the actual protocol used for authentication.

Note

While setting this property to true increases performance because the HttpListener does not send additional NTLM authentication challenges, there is a security risk in not requiring all requests to provide authentication information. You must determine whether the increase in performance is worth this risk.

Applies to