Dns.GetHostByName(String) Dns.GetHostByName(String) Dns.GetHostByName(String) Dns.GetHostByName(String) Method

Definition

Warning

This API is now obsolete.

Gets the DNS information for the specified DNS host name.

public:
 static System::Net::IPHostEntry ^ GetHostByName(System::String ^ hostName);
[System.Obsolete("Use GetHostEntry instead")]
[System.Obsolete("GetHostByName is obsoleted for this type, please use GetHostEntry instead. http://go.microsoft.com/fwlink/?linkid=14202")]
[System.Obsolete("GetHostByName is obsoleted for this type, please use GetHostEntry instead. https://go.microsoft.com/fwlink/?linkid=14202")]
public static System.Net.IPHostEntry GetHostByName (string hostName);
static member GetHostByName : string -> System.Net.IPHostEntry
Public Shared Function GetHostByName (hostName As String) As IPHostEntry

Parameters

hostName
String String String String

The DNS name of the host.

Returns

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

Exceptions

An error is encountered when resolving hostName.

Examples

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

try
{
   IPHostEntry^ hostInfo = Dns::GetHostByName( hostName );
   
   // Get the IP address list that resolves to the host names contained in the
   // Alias property.
   array<IPAddress^>^address = hostInfo->AddressList;
   
   // Get the alias names of the addresses in the IP address list.
   array<String^>^alias = hostInfo->Aliases;
   Console::WriteLine( "Host name : {0}", hostInfo->HostName );
   Console::WriteLine( "\nAliases : " );
   for ( int index = 0; index < alias->Length; index++ )
      Console::WriteLine( alias[ index ] );
   Console::WriteLine( "\nIP address list : " );
   for ( int index = 0; index < address->Length; index++ )
      Console::WriteLine( address[ index ] );
}
catch ( SocketException^ e ) 
{
   Console::WriteLine( "SocketException caught!!!" );
   Console::WriteLine( "Source : {0}", e->Source );
   Console::WriteLine( "Message : {0}", e->Message );
}
catch ( ArgumentNullException^ e ) 
{
   Console::WriteLine( "ArgumentNullException caught!!!" );
   Console::WriteLine( "Source : {0}", e->Source );
   Console::WriteLine( "Message : {0}", e->Message );
}
catch ( Exception^ e ) 
{
   Console::WriteLine( "Exception caught!!!" );
   Console::WriteLine( "Source : {0}", e->Source );
   Console::WriteLine( "Message : {0}", e->Message );
}
    try 
    {
       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(alias[index]);
       } 
       Console.WriteLine("\nIP address list : ");
       for(int index=0; index < address.Length; index++) {
          Console.WriteLine(address[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);
 }
Public Sub DisplayHostName(hostName As [String])
    Try
        ' Call the GetHostByName method, passing a DNS style host name(for example,
        ' "www.contoso.com") as an argument to obtain an IPHostEntry instance, that 
        ' contains information for the specified host.
        
        Dim hostInfo As IPHostEntry = Dns.GetHostByName(hostName)
        ' Get the IP address list that resolves to the host names contained in 
        ' the Alias property.
        Dim address As IPAddress() = hostInfo.AddressList
        ' Get the alias names of the addresses in the IP address list.
        Dim [alias] As [String]() = hostInfo.Aliases
        
        Console.WriteLine(("Host name : " + hostInfo.HostName))
        Console.WriteLine(ControlChars.Cr + "Aliases : ")
        Dim index As Integer
        For index = 0 To [alias].Length - 1
            Console.WriteLine([alias](index))
        Next index
        Console.WriteLine(ControlChars.Cr + "IP address list : ")

        For index = 0 To address.Length - 1
            Console.WriteLine(address(index))
        Next index
    Catch e As SocketException
        Console.WriteLine("SocketException caught!!!")
        Console.WriteLine(("Source : " + e.Source))
        Console.WriteLine(("Message : " + e.Message))
    Catch e As ArgumentNullException
        Console.WriteLine("ArgumentNullException caught!!!")
        Console.WriteLine(("Source : " + e.Source))
        Console.WriteLine(("Message : " + e.Message))
    Catch e As Exception
        Console.WriteLine("Exception caught!!!")
        Console.WriteLine(("Source : " + e.Source))
        Console.WriteLine(("Message : " + e.Message))
    End Try

Remarks

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.

Note

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

Security

DnsPermission
for accessing DNS information. Associated enumeration: Unrestricted

Applies to