How would I request a certificate for my virtual mailbox domains? Or my actual mailhost, which doesn’t run any web services on that domain?
In this case I have a single host, host.domain.com, which accepts mail for domain.com, domain1.com, domain2.com, domain3.com, and domain4.com, as well as serves content through nginx at vhost.domain.com, vhost1.domain.com, vhost2.domain.com, and vhost3.domain.com.
I know I need certificates for vhost*.domain.com ( or a *.domain.com wildcard!) but for the SSL/TLS mail side, what about host.domain.com, or all of the domainX.com which have nothing in DNS aside from MX records?