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  package org.apache.james.smtpserver.core.filter.fastfail;
  
  import java.net.UnknownHostException;
  import java.util.ArrayList;
  import java.util.Collection;
  import java.util.Iterator;
  
  
  import org.apache.avalon.framework.configuration.Configuration;
  import org.apache.avalon.framework.configuration.ConfigurationException;
  import org.apache.avalon.framework.service.ServiceException;
  import org.apache.avalon.framework.service.ServiceManager;
  import org.apache.avalon.framework.service.Serviceable;
  import org.apache.james.api.dnsservice.DNSService;
  import org.apache.james.api.dnsservice.TemporaryResolutionException;
  import org.apache.james.api.dnsservice.util.NetMatcher;
  import org.apache.james.dsn.DSNStatus;
  import org.apache.james.smtpserver.CommandHandler;
  import org.apache.james.smtpserver.SMTPSession;
  import org.apache.mailet.MailAddress;
  
  /**
   * This class can be used to reject email with bogus MX which is send from a authorized user or an authorized
   * network.
   */
  public class ValidRcptMX extends AbstractJunkHandler implements CommandHandler,
      Serviceable {
  
      private DNSService dnsServer = null;
  
      private static final String LOCALHOST = "localhost";
  
      private NetMatcher bNetwork = null;
  
      /**
       * @see org.apache.james.smtpserver.core.filter.fastfail.AbstractJunkHandler#configure(org.apache.avalon.framework.configuration.Configuration)
       */
      public void configure(Configuration arg0) throws ConfigurationException {
  
          Configuration[] badMX = arg0.getChildren("invalidMXNetworks");
  
          if (badMX.length != 0) {
   
              Collection bannedNetworks = new ArrayList();
  
              for (int i = 0; i < badMX.length; i++) {
                  String network = badMX[i].getValue(null);
  
                  if (network != null) {
                      bannedNetworks.add(network);
                  }
              }
  
              setBannedNetworks(bannedNetworks, dnsServer);
  
              getLogger().info("Invalid MX Networks: " + bNetwork.toString());
  
          } else {
              throw new ConfigurationException(
                  "Please configure at least on invalid MX network");
          }
          
          super.configure(arg0);
      }
  
      /**
       * Set the banned networks
       * 
       * @param networks Collection of networks 
       * @param dnsServer The DNSService
       */
      public void setBannedNetworks(Collection networks, DNSService dnsServer) {
          bNetwork = new NetMatcher(networks, dnsServer) {
              protected void log(String s) {
                  getLogger().debug(s);
              }
  
          };
      }
  
     /**
      * @see org.apache.avalon.framework.service.Serviceable#service(ServiceManager)
      */
     public void service(ServiceManager arg0) throws ServiceException {
         setDNSServer((DNSService) arg0.lookup(DNSService.ROLE));
     }
 
     /**
      * @see org.apache.james.smtpserver.CommandHandler#getImplCommands()
      */
     public Collection getImplCommands() {
         Collection c = new ArrayList();
         c.add("RCPT");
         return c;
     }
 
     /**
      * @see org.apache.james.smtpserver.CommandHandler#onCommand(SMTPSession)
      */
     public void onCommand(SMTPSession session) {
         doProcessing(session);
     }
 
     /**
      * Set the DNSService
      * 
      * @param dnsServer
      *                The dnsServer
      */
     public void setDNSServer(DNSService dnsServer) {
         this.dnsServer = dnsServer;
     }
 
     /**
      * @see org.apache.james.smtpserver.core.filter.fastfail.AbstractJunkHandler#check(org.apache.james.smtpserver.SMTPSession)
      */
     protected boolean check(SMTPSession session) {
         MailAddress rcpt = (MailAddress) session.getState().get(SMTPSession.CURRENT_RECIPIENT);
 
         String domain = rcpt.getHost();
 
         // Email should be deliver local
         if (domain.equals(LOCALHOST)) return false;
  
         Iterator mx = null;
         try {
             mx = dnsServer.findMXRecords(domain).iterator();
         } catch (TemporaryResolutionException e1) {
             //  TODO: Should we reject temporary ?
         }
 
         if (mx != null && mx.hasNext()) {
             while (mx.hasNext()) {
                 String mxRec = mx.next().toString();
 
                 try {
                     String ip = dnsServer.getByName(mxRec).getHostAddress();
 
                     // Check for invalid MX
                     if (bNetwork.matchInetNetwork(ip)) {
                         return true;
                     }
                 } catch (UnknownHostException e) {
                     // Ignore this
                 }
             }
         }
         return false;
     }
 
     /**
      * @see org.apache.james.smtpserver.core.filter.fastfail.AbstractJunkHandler#getJunkHandlerData(org.apache.james.smtpserver.SMTPSession)
      */
     public JunkHandlerData getJunkHandlerData(SMTPSession session) {
         MailAddress rcpt = (MailAddress) session.getState().get(SMTPSession.CURRENT_RECIPIENT);
         JunkHandlerData data = new JunkHandlerData();
 
         data.setRejectResponseString("530" + DSNStatus.getStatus(DSNStatus.PERMANENT, DSNStatus.SECURITY_AUTH) + " Invalid MX " + session.getRemoteIPAddress() 
             + " for domain " + rcpt.getHost() + ". Reject email");
        
         data.setJunkScoreLogString("Invalid MX " + session.getRemoteIPAddress() + " for domain " + rcpt.getHost() + ". Add JunkScore: " + getScore());
         data.setRejectLogString("Invalid MX " + session.getRemoteIPAddress() + " for domain " + rcpt.getHost() + ". Reject email");
         data.setScoreName("ValidRcptMXCheck");
         return data;
     }
 }