question about authority

[Kevin Darcy]

Kristof Loots wrote:

> Hi,
>
> I've found this in O'Reilly's "DNS and BIND"
>
> ""Name servers generally have complete information about some part of the
> domain name space, called a zone, which they load from a file on disk or
> from another name server. The name server is then said to have authority for
> that zone. Name servers can be authoritative for multiple zones, too.""
>
> I don't understand how can a name server be authoritative if the data is
> loaded from another name server?

"Authoritative" doesn't mean "original source of the data". Being authoritative
for a zone means you have the contents of the whole zone available, so you can
authoritative/definitively say whether a given name in the zone exists or not,
without having to consult another nameserver on that question. Thus, both
masters and slaves are considered "authoritative". Sure, there can be
propagation delays because information doesn't replicate instantly, but in
practice this is acceptable, and doesn't in any way diminish the
"authoritativeness" of a slave server.


- Kevin