BeginGetHostByName Method

Dns.BeginGetHostByName Method (String, AsyncCallback, Object)

Note: This API is now obsolete.

Begins an asynchronous request for IPHostEntry information about the specified DNS host name.

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

[ObsoleteAttribute("BeginGetHostByName is obsoleted for this type, please use BeginGetHostEntry instead.")]
[HostProtectionAttribute(SecurityAction.LinkDemand, ExternalThreading = true)]
public static IAsyncResult BeginGetHostByName(
	string hostName,
	AsyncCallback requestCallback,
	object stateObject


Type: System.String

The DNS name of the host.

Type: System.AsyncCallback

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

Type: System.Object

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

Return Value

Type: System.IAsyncResult

An IAsyncResult instance that references the asynchronous request.

Exception Condition

hostName is null.


An error was encountered executing the DNS query.

The asynchronous BeginGetHostByName operation must be completed by calling the EndGetHostByName method. Typically, the method is invoked by the requestCallback delegate.

This method does not block until the operation is complete. To block until the operation is complete, use the GetHostByName method.

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


This member emits trace information when you enable network tracing in your application. For more information, see Network Tracing in the .NET Framework.


for accessing DNS information. Associated enumeration: PermissionState.Unrestricted

.NET Framework
Available since 1.1
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