Configure Return Path with Gmail and Java

Question

I have a working emailer service which normally send out email through a default address, lets say admin@mycomp.com

Now I am trying to add a return-path in the email so whenever I receive an email I can directly reply to the sender email. Here's how I configure the properties:

private void sendOut() {
        props = new Properties();
        props.put("mail.smtp.host", "smtp.gmail.com");
        props.put("mail.smtp.socketFactory.port", "465");
        props.put("mail.smtp.socketFactory.class",
                "javax.net.ssl.SSLSocketFactory");
        props.put("mail.smtp.auth", "true");
        props.put("mail.smtp.port", "465");
        props.put("mail.smtp.from", "abc@google.com");
        setJavaMailProperties(props);
        Message message = new MimeMessage(getSession());
        message.setFrom(new InternetAddress("admin@mycomp.com"));
        message.setRecipients(Message.RecipientType.TO,
            InternetAddress.parse("admin@mycomp.com"));
        message.setSubject("subject");
        message.setText("content");
        Transport.send(message);

    }

However after sending out the email, I still see that the email is being sent out from my own email admin@mycomp.com. I added the mail.smtp.from based on the answer here How to set the Return-Path to an email address other than Sender address using JavaMail?. What did I miss here ?

Answer 1

It looks like from the same answer that you linked that such a service must be permitted from the server side on the smtp server to work.

It's the SMTP server who in last instance will write the Return Path header in the message that is being sent and decide at which address the replies will be sent.

1. I tried the same approach explained in the answer (setting props.put("mail.smtp.from", "abc@google.com")) without success on several SMTP clients.

2. I tried using the SMTPMessage instead of a MimeMessage as explained in another answer:

   SMTPMessage message = new SMTPMessage(session); message.setEnvelopeFrom("returnpath@hotmail.com"); ... transport.sendMessage(message, message.getAllRecipients());

This is what my smtp server responded me:

EHLO frankieta
250-smtpcmd04.ad.aruba.it hello frankieta, pleased to meet you
250-HELP
250-AUTH LOGIN PLAIN
250-SIZE 524288000
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-STARTTLS
250 OK
DEBUG SMTP: Found extension "HELP", arg ""
DEBUG SMTP: Found extension "AUTH", arg "LOGIN PLAIN"
DEBUG SMTP: Found extension "SIZE", arg "524288000"
DEBUG SMTP: Found extension "ENHANCEDSTATUSCODES", arg ""
DEBUG SMTP: Found extension "8BITMIME", arg ""
DEBUG SMTP: Found extension "STARTTLS", arg ""
DEBUG SMTP: Found extension "OK", arg ""
DEBUG SMTP: Attempt to authenticate
DEBUG SMTP: check mechanisms: LOGIN PLAIN DIGEST-MD5 NTLM 
DEBUG SMTP: AUTH LOGIN command trace suppressed
DEBUG SMTP: AUTH LOGIN succeeded
DEBUG SMTP: use8bit false
MAIL FROM:<reply_to@mail.com>
250 2.1.0 <reply_to@mail.com> sender ok
RCPT TO:<receiver@mail.it>
250 2.1.5 <original_sender@mail.it> recipient ok
DEBUG SMTP: Verified Addresses
DEBUG SMTP:   original_sender@mail.it
DATA
354 enter mail, end with "." on a line by itself
From: original_sender@mail.it
To: receiver@mail.it

The mail received from receiver@mail.it showed this headers:

Return-Path: <reply_to@mail.com>
Delivered-To: receiver@mail.it

Received: from frankieta by smtp.server.com with bizsmtp
From: original_sender@mail.it
To: receiver@mail.it

So even though the return-path was correctly set at reply_to@mail.com in the received mail, trying to reply to this message would take original_sender@mail.it as the recipient.

The envelope from will instead be usually used to bounce back error mails (wrong recipent for example). If you try to send a mail to a wrong recipient it will bounce back to the reply_to@mail.com address. So I guess it's something in the hands of the smtp server.

I hope that I helped you.