root and in-addr.arpa zone transfers

[Stephane Bortzmeyer]

On Wed, Sep 09, 2009 at 11:00:37AM -0400,
 Rick Dicaire <kritek at gmail.com> wrote 
 a message of 23 lines which said:

> Interesting....can any of the root servers be used, or must it be just
> these three?

No root server operator (except may be ISC for F) ever promised to
keep zone transfer open. It is not regarded as a mandatory
service. Therefore, the servers you list can stop this service at any
moment.