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DnsPermissionAttribute Class

Specifies permission to request information from Domain Name Servers.

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

[SerializableAttribute] 
[AttributeUsageAttribute(AttributeTargets::Assembly|AttributeTargets::Class|AttributeTargets::Struct|AttributeTargets::Constructor|AttributeTargets::Method, AllowMultiple=true, Inherited=false)] 
public ref class DnsPermissionAttribute sealed : public CodeAccessSecurityAttribute
/** @attribute SerializableAttribute() */ 
/** @attribute AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Constructor|AttributeTargets.Method, AllowMultiple=true, Inherited=false) */ 
public final class DnsPermissionAttribute extends CodeAccessSecurityAttribute
SerializableAttribute 
AttributeUsageAttribute(AttributeTargets.Assembly|AttributeTargets.Class|AttributeTargets.Struct|AttributeTargets.Constructor|AttributeTargets.Method, AllowMultiple=true, Inherited=false) 
public final class DnsPermissionAttribute extends CodeAccessSecurityAttribute
Not applicable.

The security information declared by DnsPermissionAttribute is stored in the metadata of the attribute target, which is the class to which the DnsPermissionAttribute is applied. The system then accesses this information at run time. The SecurityAction that is passed to the constructor determines the allowable DNS targets.

These security attributes are used only for Declarative Security. For Imperative Security, use the corresponding DnsPermission class.

Security access is either fully restricted or fully unrestricted. Set the Unrestricted property to true to grant access, or false for no access. Set this property as a named parameter.

For more information about using attributes, see Extending Metadata Using Attributes.

The following example uses DnsPermissionAttribute to apply declarative security to a custom class.

//Uses the DnsPermissionAttribute to restrict access only to those who have permission.

[DnsPermission(SecurityAction::Demand,Unrestricted=true)]
public ref class MyClass
{
public:
   static IPAddress^ GetIPAddress()
   {
      IPAddress^ ipAddress = Dns::Resolve( "localhost" )->AddressList[ 0 ];
      return ipAddress;
   }

};

int main()
{
   try
   {
      
      //Grants Access.
      Console::WriteLine( " Access granted\n The local host IP Address is :{0}", MyClass::GetIPAddress() );
   }
   // Denies Access.
   catch ( SecurityException^ securityException ) 
   {
      Console::WriteLine( "Access denied" );
      Console::WriteLine( securityException->ToString() );
   }

}


// Uses the DnsPermissionAttribute to restrict access only to those who 
// have permission.
/** @attribute DnsPermission(SecurityAction.Demand, Unrestricted = true)
 */
public class MyClass
{
    public static IPAddress GetIPAddress()
    {
        IPAddress ipAddress = (IPAddress)Dns.Resolve(
            "localhost").get_AddressList().get_Item(0);

        return ipAddress;
    } //GetIPAddress

    public static void main(String[] args)
    {
        try {
            //Grants Access.
            Console.WriteLine(" Access granted\n The local host IP " 
                + "Address is :" + MyClass.GetIPAddress().ToString());
        }
        // Denies Access.
        catch (System.Security.SecurityException securityException) {
            Console.WriteLine("Access denied");
            Console.WriteLine(securityException.ToString());
        }
    } //main
} //MyClass

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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, 1.1, 1.0

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