In article , ol_one2
wrote:

> When I do a dig for MX records on a non-auth server for a domain hosted
> on a set of particular public DNS servers any out-of-zone data which
> appears on the answer section isn't resolved in the additional section.
> However when I repeat the dig a few seconds later the missing
> out-of-zone data is resolved in the additional section. By example:


What I expect is happening is that the server sends out a query for that
additional data at the same time as it's sending back the response to
you. That way, the delay in responding to you is minimized, and the
additional data will be in the cache by the time you query for it the
next time.

> This problem is specific to one ISP's nameservers and is possibly the
> cause of some problems I'm having mailing companies whose domains they
> host.


There's no requirement to put these records in the Additional Data
section, it's just a convenience feature. If an application has
problems because they're not there, the application is buggy.

--
Barry Margolin, barmar@alum.mit.edu
Arlington, MA
*** PLEASE post questions in newsgroups, not directly to me ***