Let's say I have several domains. bossguy.com is the domain that hosts my mail (IMAP server) and where I ssh in to manage other domains, for example:
It makes sense to set up MX records for domain1/2/3.com to point to bossguy.com, so if someone emails me at email@example.com, it gets routed to bossguy.com for storage. But does bossguy.com need its own MX record (for emails sent to firstname.lastname@example.org)? Currently I have it set up like this:
bossguy.com. 86400 IN MX 10 mail.bossguy.com. bossguy.com 86400 IN A 23.xx.xx.xx mail.bossguy.me. 86400 IN A 23.xx.xx.xx
Is the MX record needed in this case?
Also, assume all these domains share the same IP address. Then really, they could all just have MX records that equal the domain/host (domain1.com's MX being domain1.com), and it doesn't really matter since they all share the same IP. Correct?