SslStream.BeginAuthenticateAsClient Method (String, AsyncCallback, Object)

Called by clients to begin an asynchronous operation to authenticate the server and optionally the client.

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

public virtual IAsyncResult BeginAuthenticateAsClient (
	string targetHost,
	AsyncCallback asyncCallback,
	Object asyncState
public IAsyncResult BeginAuthenticateAsClient (
	String targetHost, 
	AsyncCallback asyncCallback, 
	Object asyncState
public function BeginAuthenticateAsClient (
	targetHost : String, 
	asyncCallback : AsyncCallback, 
	asyncState : Object
) : IAsyncResult
Not applicable.



The name of the server that shares this SslStream.


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


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

Return Value

An IAsyncResult object that indicates the status of the asynchronous operation.

Exception typeCondition


targetHost is a null reference (Nothing in Visual Basic).


The authentication failed and left this object in an unusable state.


Authentication has already occurred.


Server authentication using this SslStream was tried previously.


Authentication is already in progress.


This object has been closed.

This method authenticates using Default. No client certificates are used in the authentication. The certificate revocation list is not checked during authentication.

The value specified for targetHost must match the name on the server's certificate.

The asynchronous authentication operation must be completed by calling the EndAuthenticateAsClient method. Typically, the method is invoked by the asyncCallback delegate.

This method does not block while the operation completes. To block until the operation completes, use one of the AuthenticateAsClient method overloads.

For detailed information about using the asynchronous programming model, see Calling Synchronous Methods Asynchronously

If you receive a AuthenticationException, this SslStream is no longer useable. You should close this object and remove all references to it so that it can be collected by the garbage collector.

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0