Chaining MX records illegal?

Gregory Hicks ghicks at
Thu Nov 10 06:26:38 UTC 2005

> From: Barry Margolin <barmar at>
> Subject: Re: Chaining MX records illegal?
> Date: Thu, 10 Nov 2005 01:12:20 -0500
> To: comp-protocols-dns-bind at
> In article <dku9b6$20ih$1 at>,
>  Chris De Young <chd at> wrote:
> > Hi,
> > Am I correct in my interpretation that chaining together MX records 
> > illegal,
> > despite the fact that it seems to mostly work?
> > 
> > For example:
> > 
> >	mx 10
> > .
> > .
> > .
> >	mx 10
> > 
> > is a no-no?
> There's nothing invalid about it, but it won't do what I think you 
> expect it to do.  Mail for will be delivered to 
>, not  After looking up an MX record, 
> sending system will then look up the A record of the name it gets, it 
> shouldn't look for an MX record of it.

To expand a bit...

As Barry said, that is not really "chaining" of MX records.  These are 
two SEPARATE MX records.  They are not related to each other even though 
the first points to the second.

This works as:

If you are sending mail to '', my mail server is 
"".  (look up A record)

If you are sending mail to a user at, my mail server is  (Look up A record).

I am perfectly capable of learning from my mistakes.  I will surely
learn a great deal today.

"A democracy is a sheep and two wolves deciding on what to have for
lunch.  Freedom is a well armed sheep contesting the results of the
decision." - Benjamin Franklin

"The best we can hope for concerning the people at large is that they
be properly armed." --Alexander Hamilton

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