I am extending my use of Let’s Encrypt certification from Apache to Postfix/Dovecot, over a (small) number of domains.
Reading ‘here’, many folk seem to use multiple names per domain, eg www.domain.tld, smtp.domain.tld, imap.domain.tld, mail…domain.tld, webmail.domain.tld, etc.
In Apache, I’ve set up ServerAlias www.domain.tld under (virtual) Server domain.tld, ie the names become synonyms. Currently, I have Thunderbird interacting with Postscript (SMTP) and Dovecot (IMAP) using domain.tld only; thus relying upon the ports (25 and 143) and protocols instead.
What is the advantage in listing so many server names on the certificate, as opposed to using just one ‘everywhere’?
Please advise =dn