public String getBestMxHost(String domain) throws NamingException {
        NamingEnumeration en    = getAllMxRecords(domain);
        if ( en == null ) {
            return null;
        }
        int lowestPriority  = Integer.MAX_VALUE;
        String prefHost     = null;
        while ( en.hasMore() ) {
            String x = (String) en.next();
            //System.out.println(x);
            String[] xs = x.split(" ");
            int priority    = Integer.parseInt(xs[0]);
            String mxhost   = xs[1].trim();
            //System.out.println(mxhost + " @ " + priority);
            if ( priority < lowestPriority ) {
                prefHost    = new String(mxhost);
                lowestPriority  = priority;
            }
        }
        logger.debug("Preferred MX host for " + domain + " is " + prefHost + " with a priority of " + lowestPriority);
        return prefHost;
    }

    public NamingEnumeration getAllMxRecords(String domain) throws NamingException {
        Hashtable env = new Hashtable();
        env.put("java.naming.factory.initial",
                "com.sun.jndi.dns.DnsContextFactory");
        DirContext ictx = new InitialDirContext( env );
        Attributes attrs =
           ictx.getAttributes(domain, new String[] { "MX" });
        Attribute attr = attrs.get( "MX" );
        if ( attr == null ) {
            return null;
        }
        NamingEnumeration en = attr.getAll();
        return en;
    }