I have set up a send-only server and I have tested it using mail-tester.com.
I get a 7/10, and I experience a majority of outlook/msn/hotmail inboxes sending my email to the junk folder. I do know Microsoft servers implement mitigation using black/whitelisting of IP-addresses, but I was hoping that maybe a 10/10 mail-tester score would help. I have already contacted Microsoft about them mitigating my IP, and they informed me I should try to score high on sender-reputation regardless of their policies.
I have DMARC/DKIM/SPF set up correctly, the only way I lose 3 points on mail-tester.com is because I do not have an MX Record set. From what I understand, an MX Record is not necessary for send-only email servers, however; Many posts/articles I've read online state that the lack of an MX-record is a big red-flag for recipient email servers.
My outgoing server address/FQDN is
smtp.<my-domain>.ca, there is only the one server from one IP address that sends email, and the rDNS record is set up for it.
There is a lot of conflicting information online, and I don't want to clobber my DNS entries, what is the bare minimum MX record I should use?