How to setup hybrid email routing in Stalwart - forward unknown users to external server (Google/Microsoft

[gokul5557]

I'm trying to configure a hybrid email setup in Stalwart Mail Server where:

Some users are managed locally in Stalwart

Other users are managed externally in Microsoft 365 / Google Workspace

All users use the same domain (e.g., @mydomain.com)

If a recipient is not found locally, I want to forward the email to an external server (Microsoft 365 or Google)

Current setup:

Domain: mydomain.com

Local users exist in Stalwart

External users exist in Microsoft 365

I have a relay host configured for Microsoft 365

But i don't have any idea about wha tto do next?

Question:
What is the correct condition in Stalwart's Recipient Relay to forward emails to an external server when the local user is not found?

Any examples of hybrid email routing in Stalwart would be greatly appreciated!

[mdecimus]

You need to define a strategy to do that:

https://stalw.art/docs/mta/outbound/strategy

You can check how other users have implemented it, look in the past issues/discussions for "split delivery".