Still kicking this around. It occurred to me that a nice place to be able to do this would be w/in Zimbra's mail filtering. There's no current convention for altering subjects, but I wondered if someone considered adding that functionality via a Zimlet. I've searched a bit & found this (which se...

Can you give more background? Ideally show us the commands that led to error.

Did google-ing produce any interesting hits (there's a lot unique-ish feedback to search with)?

Still chasing down possibilities, it might be possible to clear this nugget by figuring out how to invoke the header_checks on a per domain basis?

Hi All, I've got a client who is pretty interested in pre-pending "(External Sender)" to the subject of any email they receive that does not come from their own domain. I've poked around with postfix header_checks and got a POC going (on an 8.8.15 deployment) on plain old subject-editing b...

Hi John, Thanks for introducing yourself! I would certainly appreciate having Synacor/Zimbra participate in this community forum. (As you most likely know) There are many skilled enthusiasts here collaborating, offering helpful advice and sharing what they know & have experienced (I can say I've...

Exploring DKIM as well, would love to hear more on this when details are available.

Or this:

- https://aws.amazon.com/rekognition/

Imagining there's some 3rd-party who's developed (developing?) a tool that leverages something like Amazon machine learning? - https://aws.amazon.com/blogs/machine-learning/classify-your-own-images-using-amazon-sagemaker/ The use case must be classsic, hand-off the image to the image-classifier, if ...

Check it:

- https://wiki.zimbra.com/wiki/Zimbra_Releases/8.8.12/P1

Well done, thanks for sharing!