BIND 9.6 Flaw - CNAME vs. A Record in MX Records are NOT "Illegal"

[Al Stu]

No I do not believe an extra step was added.  Take the following example for 
instance.

STMP server smtp.xyz.com. needs to send a message to someone at xyz.com.  An MX 
lookup is performed for domain xyz.com. and the domain name of mx.xyz.com is 
returned.  This is the first sentence:

"When a domain name associated with an MX RR is looked up and the associated 
data field obtained, the data field of that response MUST contain a domain 
name."

Now an A lookup is performed for that domain name of mx.xyz.com. and 
returned are the name srv1.xyz.com with it's address of 1.2.3.4, and the 
alias name of mx.xyz.com is also included in the result.  This is the second 
sentence:

"That domain name, when queried, MUST return at least one address record 
(e.g., A or AAAA RR) that gives the IP address of the SMTP server to which 
the message should be directed."

@ 1800 IN A 1.2.3.4
srv1 1800 IN A 1.2.3.4
mx 1800 IN CNAME blah.xyz.com.
@ 1800 IN MX 1 mx.xyz.com.

Requirements met.