> My question is whether using an alias (CNAME) in an MX record is correct or
> not. Eg:
>
> site.com. MX 10 mail.site.com.
> mail.site.com. CNAME mailhub.site.com.
> mailhub.site.com. A 10.0.0.1
The usual rule in DNS is that anything appearing on the left-hand side
of a CNAME may not appear on the right-hand side of anything. Things
often "just work", however. YMMV.
M