Spam Filter / Whitelist suggestions

We’re a cloud subscriber, and about to go live. I wanted to send some warning to all of our new, incoming users on suggestions for preventing emails getting stuck in their spam filters.

Does anyone have a list/block of IPs that you would suggest that need to be added to people’s whitelist? I’m assuming everything comes from *, but also noticed some mailservers are using


I don’t have any special filtering for Discourse, but an examination of the headers shows the mail comes from * hosts (eg with from addresses at


Thanks for that… but would you happen to know what range of IPs that the cloud version of Discourse may be using? That would definitely help.

For instance, I received an email, headers indicating: ( Is that it, or is there a block of redundant mailservers that Discourse uses that we can make sure make it on our whitelists?

All e-mail will have an envelope sender domain of, and the SPF record for is our authoritative list of sender addresses.

We also sign with DKIM and have a DMARC record published with rejection specified if checks fail, so whitelisting ought to be sufficient.