Point domain name of my zone to name in somebody else's zone?

[Barry Margolin]

In article <mailman.171.1399542062.26362.bind-users at lists.isc.org>,
 Tony Finch <dot at dotat.at> wrote:

> Dave Warren <davew at hireahit.com> wrote:
> >
> > DNSMadeEasy calls this an "ANAME" record, internally they just lookup the
> > destination's IP and cache it, updating it as needed.
> >
> > It works, but it would be nice if this could be done in DNS. Sadly, it 
> > can't,
> > and probably won't in our lifetimes.
> 
> Never say never :-)
> 
> You can implement something ANAME-alike with a script that polls the
> A and AAAA records at the target name and does a DNS UPDATE on the owner
> as necessary, but that might not scale too well.
> 
> There are a couple of difficulties with implementing ANAME inside the
> server.
> 
> Firstly it implies a weird authoritative/recursive hybrid. A bit ugly but
> not unreasonable.
> 
> Secondly, and more importantly, is the question of how this works with
> zone transfers and secondaries. How do you ensure they support ANAME
> records? Do you include a backwards compatibility hack by adding the A and
> AAAA records to the zone?

It also has adverse implications for DNS-based CDN routing, e.g. Akamai. 
Everyone will be routed to the servers close to the auth servers of the 
domain containing the ANAME, instead of routing each end user to their 
closest servers.

-- 
Barry Margolin
Arlington, MA