To see in my firewall protocol that the requests were being dropped, I had to first turn my firewall logging on which I did by opening up a command prompt with admin rights and executing the followng:
C:\>netsh advfirewall set allprofiles logging droppedconnections enable
Ok.
Then, I sent a request with the test program and saw in the logfile (%systemroot%\system32\LogFiles\Firewall\pfirewall.log) :
2015-09-27 09:28:37 DROP UDP 192.168.178.58 239.255.255.250 52323 1900 371 - - - - - - - RECEIVE
2015-09-27 09:28:37 DROP UDP 192.168.178.58 239.255.255.250 52323 1900 357 - - - - - - - RECEIVE
2015-09-27 09:34:12 DROP TCP 192.168.178.64 66.102.1.108 58144 587 0 - 0 0 0 - - - SEND
The test program threw the following exception:
>java -classpath .;mail.jar;activation.jar SendEmailUsingGMailSMTP
Exception in thread "main" java.lang.RuntimeException: javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com,
port: 587;
nested exception is:
java.net.SocketException: Permission denied: connect
at rewards.messaging.client.SendEmailUsingGMailSMTP.main(SendEmailUsingGMailSMTP.java:64)
Caused by: javax.mail.MessagingException: Could not connect to SMTP host: smtp.gmail.com, port: 587;
nested exception is:
java.net.SocketException: Permission denied: connect
at com.sun.mail.smtp.SMTPTransport.openServer(SMTPTransport.java:1972)
..
at javax.mail.Transport.send(Transport.java:124)
Caused by: java.net.SocketException: Permission denied: connect
I should mention that with wireshark one will not see the requests because the requests don't make it beyond the firewall; however, if one clears the local DNS cache (C:\>ipconfig /flushdns), one can see with wireshark the hostname resolution request. This is nice because one can confirm that the destination address seen in the dropped TCP request is indeed the one associated with the program; the port number is also a good indication that one is looking at the correct request.
Another useful tool was openssh, which I have installed on my Windows laptop because I'm using Git Bash. With openssl, I could get Google's x509 certificate using the following:
$openssl s_client -connect smtp.gmail.com:465 -state -tls1
However, what didn't work was this:
$openssl s_client -connect smtp.gmail.com:587 -state -tls1
Loading 'screen' into random state - done
connect: Bad file descriptor
connect:errno=10013
The dropped request was also logged accordingly in the firewall's protocol similarly to that shown above.
To trouble shoot, I took the following standard snippet of code taken from here:
import javax.mail.Message; import javax.mail.MessagingException; import javax.mail.PasswordAuthentication; import javax.mail.Session; import javax.mail.Transport; import javax.mail.internet.InternetAddress; import javax.mail.internet.MimeMessage; public class SendEmailUsingGMailSMTP { public static void main(String[] args) { // Recipient's email ID needs to be mentioned. String to = "xyz@gmail.com";//change accordingly // Sender's email ID needs to be mentioned String from = "abc@gmail.com";//change accordingly final String username = "abc";//change accordingly final String password = "*****";//change accordingly // Assuming you are sending email through relay.jangosmtp.net String host = "smtp.gmail.com"; Properties props = new Properties(); props.put("mail.smtp.auth", "true"); props.put("mail.smtp.starttls.enable", "true"); props.put("mail.smtp.host", host); props.put("mail.smtp.port", "587"); // Get the Session object. Session session = Session.getInstance(props, new javax.mail.Authenticator() { protected PasswordAuthentication getPasswordAuthentication() { return new PasswordAuthentication(username, password); } }); try { // Create a default MimeMessage object. Message message = new MimeMessage(session); // Set From: header field of the header. message.setFrom(new InternetAddress(from)); // Set To: header field of the header. message.setRecipients(Message.RecipientType.TO, InternetAddress.parse(to)); // Set Subject: header field message.setSubject("Testing Subject"); // Now set the actual message message.setText("Hello, this is sample for to check send " + "email using JavaMailAPI "); // Send message Transport.send(message); System.out.println("Sent message successfully...."); } catch (MessagingException e) { throw new RuntimeException(e); } } }
