This is the sixth of a number of updates regarding the IN-ADDR.ARPA zone.
As of 2011-03-07 23:58 UTC all of the 12 root servers which were serving the IN-ADDR.ARPA zone had stopped doing so as described by ‘Planned IN-ADDR.ARPA Nameserver Change’.
The nameserver set now serving IN-ADDR.ARPA is, as described by RFC 5855:
A.IN-ADDR-SERVERS.ARPA (operated by ARIN)
B.IN-ADDR-SERVERS.ARPA (operated by ICANN)
C.IN-ADDR-SERVERS.ARPA (operated by AfriNIC)
D.IN-ADDR-SERVERS.ARPA (operated by LACNIC)
E.IN-ADDR-SERVERS.ARPA (operated by APNIC)
F.IN-ADDR-SERVERS.ARPA (operated by RIPE NCC)
One further update will be posted here in the coming days regarding the addition of the DS record for IN-ADDR.ARPA to the parent zone.