CNAME only zone?
rob0 at gmx.co.uk
Fri Dec 9 18:21:35 UTC 2011
Please do not top-post. Thank you.
On Friday 09 December 2011 11:52:58 Lightner, Jeff wrote:
> "Also note that other workarounds will solve the same problem
> in a better way."
> Care to enlighten me as to what those workarounds would be?
Not knowing the exact situation puts me at a distinct handicap in
trying to do so, but I can suggest some possibilities beyond what was
suggested by Jan-Piet and Phil.
- A cron job to look up the desired name and nsupdate(8) the A
record for shop4water.com. when that address changes
- HTTP redirects, or just a redirect for shop4water.com to point to
your desired CNAME target; www.shop4water.com *can* be a CNAME.
- Find different hosting.
> Also - why is it a registrar can do a CNAME only but we mere
> mortals can't?
Only approved registrars are allowed to update records in official
top-level domains. You can make as many CNAME records as you like,
playing by the rule that a CNAME cannot coexist with a record of the
same name and any other RRtype.
Registrars are also bound by the reality of DNS. If you want a CNAME,
they do not delegate the zone to you. They remove any NS records which
had been in place for your zone, and your nameservers are no longer in
use for that name. In fact by not being delegated, it ceases to be a
> In fact documentation from Amazon (it is
> apparently their web store I've since learned) suggests doing it
> at registrar so I'll probably go that route but I'm wondering why
> it should work there but not on one of my delegated name servers.
Phil answered this, but to restate/repeat, a delegated zone *must*
have SOA and NS records at the zone apex. Meaning: if shop4water.com
is delegated, the parent com zone at a a minimum has NS records for
shop4water.com, and your zone *must* contain SOA and NS records for
Those SOA and NS violate the rule that a CNAME cannot coexist with a
record of the same name and any other RRtype.
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