DuplicateAddressDetectionState Enum

Definition

Namespace:

System.Net.NetworkInformation

Assembly:

System.Net.NetworkInformation.dll

Specifies the current state of an IP address.

public enum class DuplicateAddressDetectionState

public enum DuplicateAddressDetectionState

type DuplicateAddressDetectionState = 

Public Enum DuplicateAddressDetectionState

Inheritance

Object

ValueType

Enum

DuplicateAddressDetectionState

Fields

Name	Value	Description
Invalid	0	The address is not valid. A nonvalid address is expired and no longer assigned to an interface; applications should not send data packets to it.
Tentative	1	The duplicate address detection procedure's evaluation of the address has not completed successfully. Applications should not use the address because it is not yet valid and packets sent to it are discarded.
Duplicate	2	The address is not unique. This address should not be assigned to the network interface.
Deprecated	3	The address is valid, but it is nearing its lease lifetime and should not be used by applications.
Preferred	4	The address is valid and its use is unrestricted.

Examples

The following code example determines unicast address information.

void DisplayUnicastAddresses()
{
   Console::WriteLine( "Unicast Addresses" );
   array<NetworkInterface^>^adapters = NetworkInterface::GetAllNetworkInterfaces();
   System::Collections::IEnumerator^ myEnum17 = adapters->GetEnumerator();
   while ( myEnum17->MoveNext() )
   {
      NetworkInterface ^ adapter = safe_cast<NetworkInterface ^>(myEnum17->Current);
      IPInterfaceProperties ^ adapterProperties = adapter->GetIPProperties();
      UnicastIPAddressInformationCollection ^ uniCast = adapterProperties->UnicastAddresses;
      if ( uniCast->Count > 0 )
      {
         Console::WriteLine( adapter->Description );
         String^ lifeTimeFormat = "dddd, MMMM dd, yyyy  hh:mm:ss tt";
         System::Collections::IEnumerator^ myEnum18 = uniCast->GetEnumerator();
         while ( myEnum18->MoveNext() )
         {
            UnicastIPAddressInformation ^ uni = safe_cast<UnicastIPAddressInformation ^>(myEnum18->Current);
            DateTime when;
            Console::WriteLine( "  Unicast Address ......................... : {0}", 
               uni->Address );
            Console::WriteLine( "     Prefix Origin ........................ : {0}", 
               uni->PrefixOrigin );
            Console::WriteLine( "     Suffix Origin ........................ : {0}", 
               uni->SuffixOrigin );
            Console::WriteLine( "     Duplicate Address Detection .......... : {0}", 
               uni->DuplicateAddressDetectionState );
            
            // Format the lifetimes as Sunday, February 16, 2003 11:33:44 PM
            // if en-us is the current culture.
            // Calculate the date and time at the end of the lifetimes.    
            when = DateTime::UtcNow + TimeSpan::FromSeconds( (double)uni->AddressValidLifetime );
            when = when.ToLocalTime();
            Console::WriteLine( "     Valid Life Time ...................... : {0}", 
               when.ToString( lifeTimeFormat, System::Globalization::CultureInfo::CurrentCulture ) );
            when = DateTime::UtcNow + TimeSpan::FromSeconds( (double)uni->AddressPreferredLifetime );
            when = when.ToLocalTime();
            Console::WriteLine( "     Preferred life time .................. : {0}", 
               when.ToString( lifeTimeFormat, System::Globalization::CultureInfo::CurrentCulture ) );
            when = DateTime::UtcNow + TimeSpan::FromSeconds( (double)uni->DhcpLeaseLifetime );
            when = when.ToLocalTime();
            Console::WriteLine( "     DHCP Leased Life Time ................ : {0}", 
               when.ToString( lifeTimeFormat, System::Globalization::CultureInfo::CurrentCulture ) );
         }
         Console::WriteLine();
      }
   }
}

public static void DisplayUnicastAddresses()
{
    Console.WriteLine("Unicast Addresses");
    NetworkInterface[] adapters  = NetworkInterface.GetAllNetworkInterfaces();
    foreach (NetworkInterface adapter in adapters)
    {
        IPInterfaceProperties adapterProperties = adapter.GetIPProperties();
        UnicastIPAddressInformationCollection uniCast = adapterProperties.UnicastAddresses;
        if (uniCast.Count >0)
        {
            Console.WriteLine(adapter.Description);
            string lifeTimeFormat = "dddd, MMMM dd, yyyy  hh:mm:ss tt";
            foreach (UnicastIPAddressInformation uni in uniCast)
            {
                DateTime when;

                Console.WriteLine("  Unicast Address ......................... : {0}", uni.Address);
                Console.WriteLine("     Prefix Origin ........................ : {0}", uni.PrefixOrigin);
                Console.WriteLine("     Suffix Origin ........................ : {0}", uni.SuffixOrigin);
                Console.WriteLine("     Duplicate Address Detection .......... : {0}",
                    uni.DuplicateAddressDetectionState);

                // Format the lifetimes as Sunday, February 16, 2003 11:33:44 PM
                // if en-us is the current culture.

                // Calculate the date and time at the end of the lifetimes.
                when = DateTime.UtcNow + TimeSpan.FromSeconds(uni.AddressValidLifetime);
                when = when.ToLocalTime();
                Console.WriteLine("     Valid Life Time ...................... : {0}",
                    when.ToString(lifeTimeFormat,System.Globalization.CultureInfo.CurrentCulture)
                );
                when = DateTime.UtcNow + TimeSpan.FromSeconds(uni.AddressPreferredLifetime);
                when = when.ToLocalTime();
                Console.WriteLine("     Preferred life time .................. : {0}",
                    when.ToString(lifeTimeFormat,System.Globalization.CultureInfo.CurrentCulture)
                );

                when = DateTime.UtcNow + TimeSpan.FromSeconds(uni.DhcpLeaseLifetime);
                when = when.ToLocalTime();
                Console.WriteLine("     DHCP Leased Life Time ................ : {0}",
                    when.ToString(lifeTimeFormat,System.Globalization.CultureInfo.CurrentCulture)
                );
            }
            Console.WriteLine();
        }
    }
}

Public Shared Sub DisplayUnicastAddresses() 

    Console.WriteLine("Unicast Addresses")
    Dim adapters As NetworkInterface() = NetworkInterface.GetAllNetworkInterfaces()
    Dim adapter As NetworkInterface
    For Each adapter In  adapters
        Dim adapterProperties As IPInterfaceProperties = adapter.GetIPProperties()
        Dim uniCast As UnicastIPAddressInformationCollection = adapterProperties.UnicastAddresses
        If uniCast.Count > 0 Then
            Console.WriteLine(adapter.Description)
            Dim lifeTimeFormat As String = "dddd, MMMM dd, yyyy  hh:mm:ss tt"
            Dim uni As UnicastIPAddressInformation
            For Each uni In  uniCast
                Dim [when] As DateTime
                
                Console.WriteLine("  Unicast Address ......................... : {0}", uni.Address)
                Console.WriteLine("     Prefix Origin ........................ : {0}", uni.PrefixOrigin)
                Console.WriteLine("     Suffix Origin ........................ : {0}", uni.SuffixOrigin)
                Console.WriteLine("     Duplicate Address Detection .......... : {0}", uni.DuplicateAddressDetectionState)
                
                ' Format the lifetimes as Sunday, February 16, 2003 11:33:44 PM
                ' if en-us is the current culture.
                ' Calculate the date and time at the end of the lifetimes.    
                [when] = DateTime.UtcNow + TimeSpan.FromSeconds(uni.AddressValidLifetime)
                [when] = [when].ToLocalTime()
                Console.WriteLine("     Valid Life Time ...................... : {0}", [when].ToString(lifeTimeFormat, System.Globalization.CultureInfo.CurrentCulture))
                [when] = DateTime.UtcNow + TimeSpan.FromSeconds(uni.AddressPreferredLifetime)
                [when] = [when].ToLocalTime()
                Console.WriteLine("     Preferred life time .................. : {0}", [when].ToString(lifeTimeFormat, System.Globalization.CultureInfo.CurrentCulture))
                
                [when] = DateTime.UtcNow + TimeSpan.FromSeconds(uni.DhcpLeaseLifetime)
                [when] = [when].ToLocalTime()
                Console.WriteLine("     DHCP Leased Life Time ................ : {0}", [when].ToString(lifeTimeFormat, System.Globalization.CultureInfo.CurrentCulture))
            Next uni
            Console.WriteLine()
        End If
    Next adapter

End Sub

Remarks

To help ensure that all interfaces on a network have a unique address, the interface host is responsible for running a "duplicate address detection" algorithm on unicast addresses. The purpose of this algorithm is to attempt to prevent non-unique addresses on the network. This process is defined in IETF RFC 1971.

This enumeration is used by the UnicastIPAddressInformation and MulticastIPAddressInformation classes. Instances of this class are returned when you retrieve the unicast address information for a NetworkInterface object.