Discourse Email Posting
meta.discourse.org/t/configure-direct-delivery-incβ¦
Discourse supports post-by-email and reply-by-email.
Github is an example of another site where you can e.g. subscribe to issues by email and then reply from your client.
You can configure Discourse to be like a mailing list, and people can post / receive only by email, OR also reply from the web interface.
You can also mirror a mailing list to Discourse with this.
Discourse mail-receiver docker image
The easy way to set this up is to run a second docker image mail-receiver. There is a sample setup available along with the main Docker image that is straight forward to install and run on the same VM where you run the main Discourse docker image.