Using the Apache Commons to send email there is the following code.
HtmlEmail email = new HtmlEmail(); email.setHostName(SMTP_HOST_NAME); email.setSmtpPort(587); email.setAuthenticator(new DefaultAuthenticator(SMTP_AUTH_USER, SMTP_AUTH_PWD)); email.setTLS(true); email.setBounceAddress("firstname.lastname@example.org"); email.setMsg("Hello"); email.setFrom("email@example.com"); email.addReplyTo("firstname.lastname@example.org"); email.addTo("email@example.com"); email.send();
But the bounce will not work. It sends the bounce to the party that authenticated the message, which in this example is SMTP_AUTH_USER. So How can I get it to bounce properly?
Did you check with a packet sniffer what is actually going over the wire? I wouldn’t be surprised if the MSA on SMPT_HOST_NAME ignores and overrides your bounce address.
You could try using the SMTP-port to the MTA and quickly check if this makes a difference.