NegotiateStream.BeginAuthenticateAsServer Method (NetworkCredential, ExtendedProtectionPolicy, ProtectionLevel, TokenImpersonationLevel, AsyncCallback, Object)

 
System_CAPS_noteNote

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Called by servers to begin an asynchronous operation to authenticate the client, and optionally the server, in a client-server connection. The authentication process uses the specified server credentials, authentication options, and extended protection policy. This method does not block.

Namespace:   System.Net.Security
Assembly:  System (in System.dll)

[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public virtual IAsyncResult BeginAuthenticateAsServer(
	NetworkCredential credential,
	ExtendedProtectionPolicy policy,
	ProtectionLevel requiredProtectionLevel,
	TokenImpersonationLevel requiredImpersonationLevel,
	AsyncCallback asyncCallback,
	object asyncState
)

Parameters

credential
Type: System.Net.NetworkCredential

The NetworkCredential that is used to establish the identity of the client.

policy
Type: System.Security.Authentication.ExtendedProtection.ExtendedProtectionPolicy

The ExtendedProtectionPolicy that is used for extended protection.

requiredProtectionLevel
Type: System.Net.Security.ProtectionLevel

One of the ProtectionLevel values, indicating the security services for the stream.

requiredImpersonationLevel
Type: System.Security.Principal.TokenImpersonationLevel

One of the TokenImpersonationLevel values, indicating how the server can use the client's credentials to access resources.

asyncCallback
Type: System.AsyncCallback

An AsyncCallback delegate that references the method to invoke when the authentication is complete.

asyncState
Type: System.Object

A user-defined object containing information about the write operation. This object is passed to the asyncCallback delegate when the operation completes.

Return Value

Type: System.IAsyncResult

An IAsyncResult object indicating the status of the asynchronous operation.

Exception Condition
ArgumentException

The CustomChannelBinding and CustomServiceNames on the extended protection policy passed in the policy parameter are both null.

ArgumentNullException

credential is null.

ArgumentOutOfRangeException

requiredImpersonationLevel must be Identification, Impersonation, or Delegation,

AuthenticationException

The authentication failed. You can use this object to retry the authentication.

InvalidCredentialException

The authentication failed. You can use this object to retry the authentication.

InvalidOperationException

Authentication has already occurred.

- or -

This stream was used previously to attempt authentication as the client. You cannot use the stream to retry authentication as the server.

NotSupportedException

Windows 95 and Windows 98 are not supported.

ObjectDisposedException

This object has been closed.

PlatformNotSupportedException

The policy parameter was set to Always on a platform that does not support extended protection.

Use the requiredProtectionLevel parameter to request security services for data transmitted using the authenticated stream. For example, to have the data encrypted and signed, specify the EncryptAndSign value. Successful authentication does not guarantee that, the requested ProtectionLevel has been granted. You must check the IsEncrypted and IsSigned properties to determine what security services are used by the NegotiateStream.

If the policy parameter is null, then an extended protection policy is used that has PolicyEnforcement set to Never.

This method is asynchronous and does not block while the operation completes. To block until the operation completes, use one of the AuthenticateAsServer method overloads.

The asynchronous authentication operation must be completed by calling the EndAuthenticateAsServer method. Typically, the method is invoked by the asyncCallback delegate. For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously

If the authentication fails, you receive an AuthenticationException or an InvalidCredentialException. In this case, you can retry the authentication with a different credential.

.NET Framework
Available since 2.0
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