I'm working on an Exchange 2010 Email server and corresponding MX records for each of it's several email domains.
Currently the DNS records for each email domain have a MX record that points to a mail host called mail.emaildomainX.com (i.e. one for each email domain)
All the mail.emaildomainX.com addresses actually point to the same server.
Do I need to do this or is this the best way because it helps when spam engines check out emails sent?