I just did a ctrl-f here for "IP space reputation"
not mentioned yet?
One of the very important things is choosing what ISP to host your self-hosted email at. And the spam blacklist (or opaque/impossible-to-know) likely blacklist status of your IP at things like office365, gmail, etc.
Assuming for a moment that you are a person who is perfectly capable of setting up your own postfix and dovecot server.
No matter how perfect your rDNS, SPF, DKIM, DMARC setup is, and how flawless your theoretical postfix or other smtp daemon configuration is... If it's not hosted in the right place, outbound mail deliverability is the main problem you'll run into.
For the persons who are not ready to host their own SMTP and mail storage, I'm going to second the other suggestions made in this same thread that say a good first step is to control the authoritative DNS for your own domain, so that you can choose where to point the MX records at, and make an educated/informed choice of third party mail service provider.
not mentioned yet?
One of the very important things is choosing what ISP to host your self-hosted email at. And the spam blacklist (or opaque/impossible-to-know) likely blacklist status of your IP at things like office365, gmail, etc.
Assuming for a moment that you are a person who is perfectly capable of setting up your own postfix and dovecot server.
No matter how perfect your rDNS, SPF, DKIM, DMARC setup is, and how flawless your theoretical postfix or other smtp daemon configuration is... If it's not hosted in the right place, outbound mail deliverability is the main problem you'll run into.
For the persons who are not ready to host their own SMTP and mail storage, I'm going to second the other suggestions made in this same thread that say a good first step is to control the authoritative DNS for your own domain, so that you can choose where to point the MX records at, and make an educated/informed choice of third party mail service provider.