So I’ve just opened a free account to manage one of my two domains. This domain I use strictly for email so there is no website. Obviously much of what Cloudflare provides is geared for websites. But I’ve seen a few recommendations of Cloudflare for mail servers specifically.
So I’m looking for some guidance on what features of my free Cloudflare service are the ones I should attend to, and which ones I can safely ignore or turn off. One more specific question under that is which DNS records do I need and not need.
For context - My Postfix mail server is on my home desktop computer, and I use it only for SMTP. The public IP is dynamic, so I’m using a free dynamic DNS hostname from Dynu. My main challenge is figuring out how to use this as my SMTP server when I’m away from home with my laptop and/or phone.
The configuration you described does not lend itself to a successful outcome. If it even is able to connect to any recipient servers, email from a dynamic residential IP is most likely to be rejected or, at best, quarantined. It would be beneficial to look into using a smarthost. If you choose one with DKIM signing capability, you will need to ensure that you publish those records in your Cloudflare DNS.
While yours is a topic that I would wild be delighted to discuss at length, it’s off-topic for the Cloudflare Community. If you find yourself with questions related to email authentication, the dmarcian forum can be a good resource.