@atridad said in Interesting read on self-hosting email, with perhaps some tidbits that'd be helpful for Cloudron in the future (i.e. monitoring):
the main difference is where the emails are stored when not in transit
This was the case up until a few years ago. Nowadays a large part is deliverability.
Every system on the internet can theoretically sent mails to any other system and this means that there are a lot of people actually using this to send spam. This has caused large providers to block out entire ip ranges and datacenters. So if you don't want to silently end up in the junk folders of gmail and office 365, your best bet is to send through them as well. Its not impossible to host your own mail, and there are still mail relays you could use to improve your chances, but it is definitely something to consider when self hosting mails.