RequestConfigurationUseDefaultCredentials Property

true if the default credentials are used; otherwise, false. The default value is false. Set this property to true when requests made by this HttpWebRequest object should, if requested by the server, be authenticated using the credentials of the currently logged on user. For client applications, this is the desired behavior in most scenarios. For middle-tier applications, such as ASP.NET applications, instead of using this property, you would typically set the Credentials property to the credentials of the client on whose behalf the request is made.

public bool UseDefaultCredentials { get; set; }