Javamail with 2 NIC, cannot connect to host port 25

Question

Hi
How do I use Javamail on a PC with 2 NIC connection? 1 to the internet and another to another network.
I tried disable the one to another network and my program can work. If both network connection is up, I received connection error to host at port 25.
Do I need to add anything to my program for it to work on 2 NIC PC?
          java.security.Security.addProvider(new com.sun.net.ssl.internal.ssl.Provider());
          //Set the host smtp address
          Properties props = new Properties();
          props.put("mail.transport.protocol", "smtp");
          props.put("mail.smtp.host", SMTP_HOST_NAME);
          props.put("mail.smtp.starttls.enable","true");
          Authenticator auth = new SMTPAuthenticator();
          //auth = null;
          Session session = Session.getDefaultInstance(props, auth);
          session.setDebug(false);
          // create a message
          Message msg = new MimeMessage(session);
          MimeBodyPart attachFilePart = new MimeBodyPart();
          FileDataSource fds = new FileDataSource(attachment);
          attachFilePart.setDataHandler(new DataHandler(fds));
          attachFilePart.setFileName(fds.getName());
          Multipart mp = new MimeMultipart();
          MimeBodyPart textPart = new MimeBodyPart();
          textPart.setContent(message, "text/plain");
          mp.addBodyPart(textPart);
          mp.addBodyPart(attachFilePart);
          InternetAddress[] addressTo = new InternetAddress[recipients.size()];
          for (int i = 0; i < recipients.size(); i++)
               addressTo[i] = new InternetAddress(recipients.get(i));
          msg.setRecipients(Message.RecipientType.TO, addressTo);
          msg.setSubject(subject);
          msg.setContent(mp);
          Transport.send(msg);Thanks for the help.
Regards,
Shawn

Answer 1

Normally the networking system on your PC will choose the appropriate interface to connect
to the host you're trying to connect to. If that's not working, it's probably a Windows problem.
Follow the JavaMail FAQ tip for debugging connection problems by connecting with telnet,
if that fails as well, it's definitely a Windows problem.