How to authenticate AD user in window server 2008

Question

hi guys,


When I use Ldap for Authenticate user by IP address in winow server 2012. Its working fine ,
but when when i use same code in window server 2008 ,its not working.please tell some solution . My code as below.

        Errmsg = "";

        string domainAndUsername = "192.168.0.68"+ @"\" + "amar";

        DirectoryEntry entry = new DirectoryEntry(192.168.0.68", domainAndUsername, "ABCD");

        try

        {

            // Bind to the native AdsObject to force authentication.

           // entry.AuthenticationType = AuthenticationTypes.SecureSocketsLayer;

            Object obj = entry.NativeObject;

            DirectorySearcher search = new DirectorySearcher(entry);

            search.Filter = "(SAMAccountName=" + username + ")";

            search.PropertiesToLoad.Add("cn");

            SearchResult result = search.FindOne();

            if (null == result)

            {

                return false;

            }

            // Update the new path to the user in the directory

            LdapPath = result.Path;

            string _filterAttribute = (String)result.Properties["cn"][0];

        }

        catch (Exception ex)

        {

            Errmsg = ex.Message;

            return false;

            throw new Exception("Error authenticating user." + ex.Message);

        }

        return true;

   
need your help.
Thanks and regards
      Amar