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

[David Sparks]

Michael Milligan wrote:
> You just don't get it.  You are off wandering around in the weeds.
> 
> Read the tail end of Chapter 5 in the book "DNS and BIND" describing the
> MX selection algorithm in layman's terms to (perhaps) understand why
> having MX records referencing CNAMEs is bad.
> 
> It may work right now for you, but referencing CNAMEs in MX records
> eventually _will_ cause delivery loops the next time you accidentally
> fat-finger a config.  If you continue to be hard-headed about this and
> not listen to the 100s of years of collective wisdom dispensed, then go
> ahead and leave yourself set up for a potential DoS against yourself,
> we're not going to stop you...  and we're not going to feel sorry for
> you either.

There are plenty of ways to get a mail loop that don't involve DNS
mis-configuration.  As such pretty much every major MTA detects and stops mail
loops.

So mail loops are a non-issue ... next?

ds



> FIN
> 
> Regards,
> Mike
> 
> Al Stu wrote:
>> Analyze this.
>>
>> Query MX dns.com
>>
>> Response MX nullmx.domainmanager.com
>>
>> Query A nullmx.domainmanager.com
>>
>> Response CNAME mta.dewile.net, A 64.40.103.249
>>
> 
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