SslStream.BeginAuthenticateAsServer Method (X509Certificate, Boolean, SslProtocols, Boolean, AsyncCallback, Object)


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Called by servers to begin an asynchronous operation to authenticate the server and optionally the client using the specified certificates, requirements and security protocol.

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

[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public virtual IAsyncResult BeginAuthenticateAsServer(
	X509Certificate serverCertificate,
	bool clientCertificateRequired,
	SslProtocols enabledSslProtocols,
	bool checkCertificateRevocation,
	AsyncCallback asyncCallback,
	object asyncState


Type: System.Security.Cryptography.X509Certificates.X509Certificate

The X509Certificate used to authenticate the server.

Type: System.Boolean

A Boolean value that specifies whether the client is asked for a certificate for authentication. Note that this is only a request -- if no certificate is provided, the server still accepts the connection request.

Type: System.Security.Authentication.SslProtocols

The SslProtocols value that represents the protocol used for authentication.

Type: System.Boolean

A Boolean value that specifies whether the certificate revocation list is checked during authentication.

Type: System.AsyncCallback

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

Type: System.Object

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

Return Value

Type: System.IAsyncResult

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

Exception Condition

serverCertificate is null.


enabledSslProtocols is not a valid SslProtocols value.


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.


The BeginAuthenticateAsServer method is not supported on Windows 95, Windows 98, or Windows Millennium.

The asynchronous authentication operation must be completed by calling the EndAuthenticateAsServer 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 AuthenticateAsServer 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.


The BeginAuthenticateAsServer method is not supported.

.NET Framework
Available since 2.0
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