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

[Al Stu]

I not only say it, I have demonstrated it.
BIND is the DNS system we are discussing.
Have not looked to see if that specifically is spec'ed in an RFC.
Yes other DNS implementations do return both the A and CNAME.

*** PLEASE don't copy me on replies, I'll read them in the group ***


----- Original Message ----- 
From: <bsfinkel at anl.gov>
To: <bind-users at lists.isc.org>
Sent: Tuesday, January 27, 2009 9:52 AM
Subject: e: BIND 9.6 Flaw - CNAME vs. A Record in MX Records are NOT 
"Illegal"


> Al Stu" <Al_Stu at Verizon.net> wrote:
>
>>How about these two?
>>
>>> nullmx.domainmanager.com
>>Non-authoritative answer:
>>Name:    mta.dewile.net
>>Address:  69.59.189.80
>>Aliases:  nullmx.domainmanager.com
>>
>>> smtp.secureserver.net
>>Non-authoritative answer:
>>Name:    smtp.where.secureserver.net
>>Address:  208.109.80.149
>>Aliases:  smtp.secureserver.net
>>
>>There are two reasons it does not blow up in peoples face.  1) If it is in
>>the CNAME RR points to an A record in the same zone, both the A record and
>>the CNAME record are returned, thus meeting the A record requirement.  2)
>>SMTP servers are required to accept an alias and look it up.  Thus there 
>>is
>>no need for this.
>>
>>And no it does not matter if there are multiple MX records with different
>>preferences values.
>
> You say, "both the A record and the CNAME record are returned."
> We know that BIND does this.  Is this part of the RFC?  Do other DNS
> implementation return both the "A" and the CNAME?
> ----------------------------------------------------------------------
> Barry S. Finkel
> Computing and Information Systems Division
> Argonne National Laboratory          Phone:    +1 (630) 252-7277
> 9700 South Cass Avenue               Facsimile:+1 (630) 252-4601
> Building 222, Room D209              Internet: BSFinkel at anl.gov
> Argonne, IL   60439-4828             IBMMAIL:  I1004994
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