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Dns.GetHostByName Method (String)


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Note: This API is now obsolete.

Gets the DNS information for the specified DNS host name.

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

[ObsoleteAttribute("GetHostByName is obsoleted for this type, please use GetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202")]
public static IPHostEntry GetHostByName(
	string hostName


Type: System.String

The DNS name of the host.

Return Value

Type: System.Net.IPHostEntry

An IPHostEntry object that contains host information for the address specified in hostName.

Exception Condition

hostName is null.


The length of hostName is greater than 255 characters.


An error is encountered when resolving hostName.

The GetHostByName method queries the Internet DNS server for host information. If you pass an empty string as the host name, this method retrieves the standard host name for the local computer.

For asynchronous access to DNS information, use the BeginGetHostByName and EndGetHostByName methods.

If the Ipv6Element.Enabled property is set to true, the Aliases property of the IPHostEntry instance returned is not populated by this method and will always be empty.


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

The following example uses the GetHostByName method to get the DNS information for the specified DNS host name.

       IPHostEntry hostInfo = Dns.GetHostByName(hostName);
       // Get the IP address list that resolves to the host names contained in the 
       // Alias property.
       IPAddress[] address = hostInfo.AddressList;
       // Get the alias names of the addresses in the IP address list.
       String[] alias = hostInfo.Aliases;

       Console.WriteLine("Host name : " + hostInfo.HostName);
       Console.WriteLine("\nAliases : ");
       for(int index=0; index < alias.Length; index++) {
       Console.WriteLine("\nIP address list : ");
       for(int index=0; index < address.Length; index++) {
    catch(SocketException e) 
       Console.WriteLine("SocketException caught!!!");
       Console.WriteLine("Source : " + e.Source);
       Console.WriteLine("Message : " + e.Message);
    catch(ArgumentNullException e)
Console.WriteLine("ArgumentNullException caught!!!");
       Console.WriteLine("Source : " + e.Source);
       Console.WriteLine("Message : " + e.Message);
 catch(Exception e)
  Console.WriteLine("Exception caught!!!");
  Console.WriteLine("Source : " + e.Source);
  Console.WriteLine("Message : " + e.Message);


for accessing DNS information. Associated enumeration: PermissionState.Unrestricted

.NET Framework
Available since 1.1
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