I've got a requirement to provide subdomain-specific MX records while serving HTTP traffic at
customer.oldandbusted.com, something like this:
customer1.oldandbusted.com. IN A 192.168.0.1 customer1.oldandbusted.com. IN MX 10 mail.customer1.com customer2.oldandbusted.com. IN A 192.168.0.2 customer2.oldandbusted.com. IN MX 10 mail.customer2.com
Let's say I want to roll out another zone, something like this:
customer1.newhotness.com CNAME customer1.oldandbusted.com customer2.newhotness.com CNAME customer2.oldandbusted.com
It is my understanding RFC1034 specifies that when encountering a CNAME the DNS software should use the provided value for all record types, A, MX, TXT, etc.
My question is does email addressed to email@example.com really get delivered to mail.customer1.com? Does anyone have experience doing this? Does it really work? Do MTAs correctly interpret the CNAME and resolve the MX recoed, or is this just crazytalk that could be hit-or-miss?