Eclipse, Javamail, Tomcat, and socket unreachable / network unreachable?

I have a regular Java Application that works with Javamail. As in, if I just run it in a Main(String[] args) it will work but if I'm running it from a webapp, specifically VAADIN with Tomcat (AND Jetty), I always get a java.net.SocketException: network is unreachable: connect

I can ping the MSExchange server. And the regular program works.

In eclipse, I tried following this guide by changing the server.xml and web.xml settings, but after adding in all th changes, I still get the same error.

This is the Java Application that works in Eclipse, it will send an email using the MSExchange server we have. Are there specific ports I need to add? I've tried to force Tomcat to use IPV4 by adding 0.0.0.0 to all my connectors but that didn't do anything.

import java.util.Calendar;
import java.util.Date;
import java.util.Properties;

import javax.mail.Session;

import java.text.SimpleDateFormat;

public class SendEmail {
    public static void main(String[] args) {
          //Creates a connection with the Exchange Server.
        String smtpHostServer = "MSExchangeServerName";

        Properties props = System.getProperties();
        props.put("mail.smtp.host", smtpHostServer);
        props.put("mail.smtp.auth", "false");
        props.put("mail.smtp.socketFactory.port", "25");
        props.put("java.net.preferIPv4Stack","True");
        Session session = Session.getInstance(props, null);

        String todayStr = new SimpleDateFormat("MM-dd-yyyy").format(new Date());

        Calendar c = Calendar.getInstance();
        c.add(Calendar.DAY_OF_MONTH, 14);
        Date d = c.getTime();
        String dateStr = new SimpleDateFormat("MM/dd/yyyy").format(d);

        SendEmailUtility.sendEmail(session, "[email protected]", "Test <b>Email</b>");

Here is the SendEmailUtility:

import javax.activation.DataHandler;
import javax.activation.DataSource;
import javax.activation.FileDataSource;
import javax.mail.BodyPart;
import javax.mail.Message;
import javax.mail.Session;
import javax.mail.Transport;
import javax.mail.internet.InternetAddress;
import javax.mail.internet.MimeBodyPart;
import javax.mail.internet.MimeMessage;
import javax.mail.internet.MimeMultipart;

public class SendEmailUtility {
    public static void sendEmail(Session session, String toEmail, String subject, String body){   
        try        
        {          
            //Create a default MimeMessage object.
         Message message = new MimeMessage(session);

         // Set From: header field of the header.
         message.setFrom(new InternetAddress("[email protected]"));

         // Set To: header field of the header.
         message.setRecipients(Message.RecipientType.TO,InternetAddress.parse(toEmail));

         // Set Subject: header field
         message.setSubject(subject);

         // This mail has 2 part, the BODY and the embedded image
         MimeMultipart multipart = new MimeMultipart("related");

         // first part (the html)
         BodyPart messageBodyPart = new MimeBodyPart();
         String htmlText = "<img src=\"cid:image\"><p>"+body;
         messageBodyPart.setContent(htmlText, "text/html");
         // add it
         multipart.addBodyPart(messageBodyPart);

         // second part (the image)
         messageBodyPart = new MimeBodyPart();
         String fdsImg;
        fdsImg = "c:\download.jpg";

         DataSource fds = new FileDataSource(fdsImg);

         messageBodyPart.setDataHandler(new DataHandler(fds));
         messageBodyPart.setHeader("Content-ID", "<image>");

         // add image to the multipart
         multipart.addBodyPart(messageBodyPart);

         // put everything together
         message.setContent(multipart);
         // Send message
         Transport.send(message); //ERROR HAPPENS HERE ON TOMCAT
        }
        catch (Exception e) {          
            e.printStackTrace();        
        }    
    }
}

This is the exactly same copy pasted code in the webapp with the exact same EmailUtils above, only that this version DOESN'T WORK.

btnSendEmail.addClickListener(new ClickListener(){

        @Override
        public void buttonClick(ClickEvent event) {
            try {
                String smtpHostServer = "MSExchangeServerName";

                Properties props = System.getProperties();
                props.put("mail.smtp.host", smtpHostServer);
                props.put("mail.smtp.auth", "false");
                props.put("mail.smtp.socketFactory.port", "25");
                props.put("java.net.preferIPv4Stack","True");
                Session session = Session.getInstance(props, null);

                String todayStr = new SimpleDateFormat("MM-dd-yyyy").format(new Date());

                Calendar c = Calendar.getInstance();
                c.add(Calendar.DAY_OF_MONTH, 14);
                Date d = c.getTime();
                String dateStr = new SimpleDateFormat("MM/dd/yyyy").format(d);

                SendEmailUtility.sendEmail(session, "[email protected]", "test <b>email");


            } catch (Exception e) {
                e.printStackTrace();
                Notification.show("Error sending the email", Notification.Type.ERROR_MESSAGE);
    }
        }

       });


       layout.addComponent(btnSendEmail);

My Stacktrace:

javax.mail.MessagingException: Could not connect to SMTP host: MSExchangeName, port: 25;
  nested exception is:
    java.net.SocketException: Network is unreachable: connect
    at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1972)
    at com.sun.mail.smtp.SMTPTransport.protocolConnect(SMTPTransport.java:642)
    at javax.mail.Service.connect(Service.java:295)
    at javax.mail.Service.connect(Service.java:176)
    at javax.mail.Service.connect(Service.java:125)
    at javax.mail.Transport.send0(Transport.java:194)
    at javax.mail.Transport.send(Transport.java:124)
    at org.test.EmailUtils.sendEmail(EmailUtils.java:57)

Are there any other options I have to do or that I might not have done correctly? As a shot in the dark, I tried looking up eclipse, javamail, tomcat and I got this question and added the Javamail jar to my Tomcat Lib folder and also in my classpath. I still get the cannot connect error.

When I Right Click > Run as >Run on server, I tried to see if Tomcat was running on a system account, but when I checked in Task Manager, it had my Username under here:

Does this mean it has access to the network? Or something is still blocked? Or I need to add proxy settings specifically for Tomcat?

Solution

Sounds like a firewall or anti-virus problem. The JavaMail FAQ has connection debugging tips.