[dns-operations] AXFR support for custom DNS features (Was: Recommended zone serial number format for over 100 changes / day)

Robert robert at longwinters.org
Fri Apr 1 17:13:08 UTC 2016

On 1 April 2016 at 09:42, Andrew Sullivan <ajs at anvilwalrusden.com> wrote:
> On Fri, Apr 01, 2016 at 09:11:36AM -0700, Robert wrote:
>> attempt to send notifies, how would you want things that aren't
>> supported in native BIND represented in the AXFR?  For example, Alias,
>> LBR, Geo, and WRR (to name just a few) don't have record types in
>> native BIND - what would that look like in an AXFR?
> Apart from the point about some of them not actually being RRs, if
> they _are_ RRs, they'll transfer just fine.  They're merely treated as
> unknown RRTYPEs, like everywhere else.
> Best regards,

So then the preference would be dropped?  Just trying to understand
how people would find that useful.  For example, most DNS providers
have some notion of weighted round robin records.

Say I had a WRR like:

   "www.mycompany.com": {
        "": {
            "weight": 10,
        "": {
            "weight": 100,

Would you flatten out the weight into:

www.mycompany.com IN A
www.mycompany.com IN A

Or would you expect them to be totally dropped as unknown RRTYPEs?  I
think either case is bad from an operational standpoint.

Please forgive my ignorance, I don't use AXFR and I'm just trying to
educate myself on how people would expect this to work because I often
hear people wanting this feature from various commercial DNS
providers, most of whom support features which are not supported by

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