Plesk Onyx VPS (Ubuntu) intended to host multiple domains for some low traffic small businesses. Each domain needs to be able to send email from the server using their domain.
Hostname not specified during setup, I assumed from my experience w/other hosting companies that a default generic but FQDN hostname would get assigned, I know now that's not the case at Vultr. Instead, it defaulted to "localhost:localdomain", which immediately got the server's IP address blacklisted at SpamHaus.org when a few test emails were sent from the VPS.
After some back and forth w/support, it appears that my best (only?) option, and for now at least I don't want to use a third party SMTP service, is to get a generic domain of my own and use it for the server's hostname, assigning it a sub-domain and setting up an A record for it to point to this server's IP address so that reverse DNS/PTR resolves correctly.
Anyone else already done this? If so, does my explanation for how it needs to be set up sound right?
i.e., using a generic domain that I own:
sub-domain A record > 18.104.22.1681
where sub-domain.my_domain.com is the server's hostname.