Pointing MX Records at CNAMES

[Martin McCormick]

	Is it or is it not legal to point a MX record at a name
which is actually an alias for another system?

	I have always thought not, but I am writing some rules in
a C program that keeps track of entries in our dns data base and
I want to be sure I am thinking along the right lines.

	As a test, I created a CNAME for a system, then an MX
record and made it point to that CNAME.

	Bind didn't complain, but the nslookup program only
resolved the MX record to the CNAME and didn't produce anything
past that point so I am not sure had there been important spam
headed to that CNAME if it would have actually arrived.

	I know that one may not have a MX and CNAME record with
the same name, nor can you have a CNAME that has the same name as
an A record, but I am not sure about MX's pointing to CNAMES.

Martin McCormick