Get Remote MAC Address Through IPv6

Question

Can I get a MAC from another PC on the same network via IPv6 (without WMI)? With IPv4, this is easy (ARP).

IPv6 uses the Neighbor Discovery Protocol (NDP) to obtain the MAC address. Are there any methods for this in .Net?

Answer 1

You can run the external command "netsh int ipv6 show neigh" and filter out the host you are interested in. You needed to contact him immediately before this, so you know that he is in NC.

API , GetIpNetTable2 , , ResolveIpNetEntry2. , .NET API, PInvoke.

Answer 2

Martin Windows, , GNU/Linux * nix .

neigh ip IPv6, :

$ ip -6 neigh
fe80::200:ff:fe00:0 dev eth0 lladdr 00:0e:54:24:23:21 router REACHABLE
fe80::202:b0ff:fe01:2abe dev eth0 lladdr 00:02:b0:02:2a:be DELAY

(: -6 ARP IPv4, IPv6 ND .)

, MAC- all IPv6 , , , , :

$ ping6 ff02::1%eth0
64 bytes from fe80::221:84ff:fe42:86ef: icmp_seq=1 ttl=64 time=0.053 ms # <-- you
64 bytes from fe80::200:ff:fe00:0: icmp_seq=1 ttl=64 time=2.37 ms (DUP!)
64 bytes from fe80::202:b0ff:fe01:2abe: icmp_seq=1 ttl=64 time=2.38 ms (DUP!)
64 bytes from fe80::215:abff:fe63:f6fa: icmp_seq=1 ttl=64 time=2.66 ms (DUP!)

$ ip -6 neigh
fe80::200:ff:fe00:0 dev eth0 lladdr 00:0e:54:24:23:21 router REACHABLE
fe80::202:b0ff:fe01:2abe dev eth0 lladdr 00:02:b0:02:2a:be DELAY
fe80::215:abff:fe63:f6fa dev eth0 lladdr 00:02:15:ab:f6:fa DELAY # <-- a new one!

Answer 3

A response from @Alex would be better if the parsing code was improved. Here is one way:

public static string netsh(String IPv6)
{
    IPAddress wanted;
    if (!IPAddress.TryParse(IPv6, out wanted))
        throw new ArgumentException("Can't parse as an IPAddress", "IPv6");

    Regex re = new Regex("^([0-9A-F]\S+)\s+(\S+)\s+(\S+)", RegexOptions.IgnoreCase);

    // ... the code that runs netsh and gathers the output.

        Match m = re.Match(output);
        if (m.Success)
        {
            // [0] is the entire line
            // [1] is the IP Address string
            // [2] is the MAC Address string
            // [3] is the status (Permanent, Stale, ...)
            //
            IPAddress found;
            if (IPAddress.TryParse(m.Groups[1].Value, out found))
            {
                 if(wanted.Equals(found))
                 {
                      return m.Groups[2].Value;
                 }
            }
        }

    // ... the code that finishes the loop on netsh output and returns failure
}

Answer 4

Here is my code:

public static string netsh(String IPv6)
         {
           Process p = new Process();
           p.StartInfo.FileName = "netsh.exe";
           String command = "int ipv6 show neigh"; 
           Console.WriteLine(command);
           p.StartInfo.Arguments = command;
           p.StartInfo.UseShellExecute = false;
           p.StartInfo.RedirectStandardOutput = true;
           p.Start();

          String output = "go";
          while (output!=null){
            try
             {
               output = p.StandardOutput.ReadLine();
             }
             catch (Exception)
             {
               output = null;
             }
             if (output.Contains(IPv6))
             {
               // Nimmt die Zeile in der sich die IPv6 Addresse und die MAC Addresse des Clients befindet
               // Löscht den IPv6 Eintrag, entfernt alle Leerzeichen und kürzt den String auf 17 Zeichen, So erschein die MacAddresse im Format "33-33-ff-0d-57-00"

               output = output.Replace(IPv6, "").Replace(" ", "").TrimToMaxLength(17) ;
               return output;
             }
           }
           return null;

        }