Forwarding of auto-responses sent to the return-path
Delayed bounce messages sent to the return path are correctly processed by Mailgun (if the MX records are set).
But other kind of messages sent the return path address, like vacation or out of office auto-responses are simply ignored and dropped.
It would be great to be notified when an auto-response is sent to the return path address, by forwarding and/or using a webhook.
The fact that not all `delayed bounces` sent to the return-path can be caught via routes or webhook is really critical for us and our clients since Captcha challenges (whitelist) are sometimes widely used in some industries/regions. And auto-replies to notify of a change of email address (and out of office) are also useful to catch in certain situations.
It would be really useful to have *some* way of catching those instead of just catching the technical delayed bounces and just dropping everything else with no warning!
Additionally some services like my eFax uses the return path to authenticate the services and reply back with status updates. This fails with using the mailgun service.
In fact, I would prefer to handle responses to the Return-Path address manually (as mailgun does not do anything useful with such replies anyway) -- it is not that many of them. However, when it seems that Mailgun ignores h:Return-path headers and forces its own address as the Return-path header. Not good...
Sometimes people have auto-response message set to 'My new address is ...' -- these are extremely useful for keeping the mailing list clean and up to date. Another example is Captcha tests that some people add to protect their mailboxes from spam -- we would prefer to see such requests and actually solve the Captchas manually (to make sure our messages are delivered to more people) rather than simply being unaware of that happening.