The following code works fine, but it requires hard coding in a DNS
server IP or name.  I vaguely recall there is a new way to do this
where it finds a DNS server on its own, or there is a new method to
dynamically find a DNS server.

 /**
    * Gets all matching dns records as an array of strings.
    *
    * @param domain domain, e.g. oberon.ark.com or oberon.com which
you want
    *               the DNS records.
    * @param types  e.g."MX","A" to describe which types of
    *               record you want.
    *
    * @return ArrayList of Strings
    *
    * @throws NamingException if DNS lookup fails.
    */
   private static ArrayList<String> getDNSRecs( String domain,
                                                String... types )
throws NamingException
       {
       ArrayList<String> results = new ArrayList<String>( 15 );
       DirContext ictx = new InitialDirContext();
       Attributes attrs =
               ictx.getAttributes( "dns://" + DNS_SERVER + "/" +
domain,
                                   types );
       for ( Enumeration e = attrs.getAll(); e.hasMoreElements(); )
           {
           Attribute a = (Attribute) e.nextElement();
           int size = a.size();
           for ( int i = 0; i < size; i++ )
               {
               // MX string has priority (lower better) followed by
associated mailserver
               // A string is just IP
               results.add( (String) a.get( i ) );
               }// end inner for
           }// end  outer for
       if ( DEBUGGING && results.size() == 0 )
           {
           System.err.println( "Failed to find any DNS records for
domain " + domain );
           }
       return results;
       }
--

Roedy Green Canadian Mind Products
The Java Glossary
http://mindprod.com