How can I send an email when the SMTP domain it was sent from doesn't match the domain in the "From:"? about simple-java-mail HOT 5 CLOSED

Seems like a server policy to disallow from addresses that don't match the username. I'm not sure what I can do about this.

from simple-java-mail.

I did some research and I found that even though we can't force the server to ignore its policy, but we can try to appease it by setting the "Sender" header on the envelope.

Before I add this as a nice API, could you please try using the following example:

currentMailerBuilder
    .withHeader("Sender", "[email protected]")

from simple-java-mail.

Hi, thanks for replying!

I tried your suggestion and sadly the result is the same. I can send the mail succesfully only if I set the sender header to be the [email protected] and leave from as [email protected] , but of course this does not result in the desired behavior from my example screenshot above.

In the quarkus mailer case I achieve it like this:

Mail.withHtml(to, subject, html)
                .addHeader("From", fromHeader)
                .addHeader("Reply-To", fromHeader);

Given that it is the exact same case (same domain, SMTP server, user, "from" address and recipient, etc)
So basically I add a "from" header manually which differs from the domain of my SMTP. It seems like somehow the quarkus mailer gets around this server policy (it could be a security issue on the SMTP server side as far as I know).

I tried adding a "from" header manually in simple-java-mail too, but I cannot build a valid email without specifiying a value for from() in the EmailBuilder, and of course if I add both from() and then add manually a "from" header - gmail refuses to deliver the message with this:

 host gmail-smtp-in.l.google.com
    said: 550-5.7.1  Our system has detected that this message
    is not RFC 550-5.7.1 5322 compliant: 550-5.7.1 Multiple 'From' headers
    found. 550-5.7.1 To reduce the amount of spam sent to Gmail, this message
    has been 550-5.7.1 blocked.

If you have any ideas - they will would be highly aprreciated, meanwhile if I find out what's the difference between the outputs of the quarkus mailer and simple-java-mail - I will let you know.
Thank you!

from simple-java-mail.

I would be interested in the two EML outputs of the MimeMessage object from both Quarkus and Simple Java Mail and see how the headers differ.

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Closed as inactionable.

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