The credentials returned by the CredentialCache.DefaultNetworkCredentials property is applicable only for NTLM, negotiate, and Kerberos-based authentication.

The credentials returned by CredentialCache.DefaultNetworkCredentials represents the authentication credentials for the current security context in which the application is running. For a client-side application, these are usually the Windows credentials (user name, password, and domain) of the user running the application. For ASP.NET applications, the default network credentials are the user credentials of the logged-in user, or the user being impersonated.