Unable to slave root zones

[Mark Knight]

I've just noticed (after the slave zones expired), that the root name 
servers have been refusing my zone transfer requests since the end of March.

My confirm is per the standard named.conf example, e.g.:

zone "." {
         type slave;
         file "/usr/local/etc/namedb/slave/root.slave";
         masters {
                 192.5.5.241;    // F.ROOT-SERVERS.NET.
         };
         allow-query { localnets; };
         notify no;
};

Apr  7 00:06:29 steamer named[25909]: transfer of './IN' from 
192.5.5.241#53: Transfer status: REFUSED
Apr  7 13:21:20 steamer named[550]: transfer of 'arpa/IN' from 
192.5.5.241#53: Transfer status: REFUSED

I cannot find any announcement that this is now disallowed, any ideas 
what's changed or how I should do this?

Thanks, Mark
-- 
Mark Knight
Mobile: +44 7753 250584.  http://www.knigma.org/
Email: markk at knigma.org.  Skype: knigma