DnsPermissionAttribute Class

Definition

Namespace:

System.Net

Assembly:

System.Security.Permissions.dll

Caution

Code Access Security is not supported or honored by the runtime.

Specifies permission to request information from Domain Name Servers.

public ref class DnsPermissionAttribute sealed : System::Security::Permissions::CodeAccessSecurityAttribute

[System.AttributeUsage(System.AttributeTargets.Assembly | System.AttributeTargets.Class | System.AttributeTargets.Constructor | System.AttributeTargets.Method | System.AttributeTargets.Struct, AllowMultiple=true, Inherited=false)]
[System.Obsolete("Code Access Security is not supported or honored by the runtime.", DiagnosticId="SYSLIB0003", UrlFormat="https://aka.ms/dotnet-warnings/{0}")]
public sealed class DnsPermissionAttribute : System.Security.Permissions.CodeAccessSecurityAttribute

[<System.AttributeUsage(System.AttributeTargets.Assembly | System.AttributeTargets.Class | System.AttributeTargets.Constructor | System.AttributeTargets.Method | System.AttributeTargets.Struct, AllowMultiple=true, Inherited=false)>]
[<System.Obsolete("Code Access Security is not supported or honored by the runtime.", DiagnosticId="SYSLIB0003", UrlFormat="https://aka.ms/dotnet-warnings/{0}")>]
type DnsPermissionAttribute = class
    inherit CodeAccessSecurityAttribute

Public NotInheritable Class DnsPermissionAttribute
Inherits CodeAccessSecurityAttribute

Inheritance

Object

Attribute

SecurityAttribute

CodeAccessSecurityAttribute

DnsPermissionAttribute

Attributes

AttributeUsageAttribute ObsoleteAttribute

Examples

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() );
   }

}

public class MyClass
{
    public static IPAddress GetIPAddress()
    {
        IPAddress ipAddress = Dns.Resolve("localhost").AddressList[0];
        return ipAddress;
    }
    public static void Main()
    {
        try
        {
            //Grants Access.
            Console.WriteLine(" Access granted\n The local host IP Address is :" +
                                  MyClass.GetIPAddress().ToString());
        }
        // 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.
<DnsPermission(SecurityAction.Demand, Unrestricted := true)>  _
Public Class MyClass1
   
   Public Shared Function GetIPAddress() As IPAddress
      Dim ipAddress As IPAddress = Dns.Resolve("localhost").AddressList(0)
      Return ipAddress
   End Function 'GetIPAddress
   
   Public Shared Sub Main()
      Try
         ' Grants Access.
         Console.WriteLine(("Access granted" + ControlChars.NewLine + " The local host IP Address is :" + MyClass1.GetIPAddress().ToString()))
      ' Denies Access.
      Catch securityException As SecurityException
         Console.WriteLine("Access denied")
         Console.WriteLine(securityException.ToString())
      End Try
   End Sub
End Class

Remarks

Caution

Code Access Security (CAS) has been deprecated across all versions of .NET Framework and .NET. Recent versions of .NET do not honor CAS annotations and produce errors if CAS-related APIs are used. Developers should seek alternative means of accomplishing security tasks.

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 Attributes.

Constructors

DnsPermissionAttribute(SecurityAction)

Initializes a new instance of the DnsPermissionAttribute class with the specified SecurityAction value.

Properties

Action	Gets or sets a security action. (Inherited from SecurityAttribute)
TypeId	When implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute)
Unrestricted	Gets or sets a value indicating whether full (unrestricted) permission to the resource protected by the attribute is declared. (Inherited from SecurityAttribute)

Methods

CreatePermission()	Creates and returns a new instance of the DnsPermission class.
Equals(Object)	Returns a value that indicates whether this instance is equal to a specified object. (Inherited from Attribute)
GetHashCode()	Returns the hash code for this instance. (Inherited from Attribute)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IsDefaultAttribute()	When overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute)
Match(Object)	When overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute)
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
ToString()	Returns a string that represents the current object. (Inherited from Object)

See also

• CodeAccessSecurityAttribute