U.S. Army Research LaboratoryU.S. Army Research Laboratory

H-Root will change its addresses on 1 December 2015

This is advance notice that there is a scheduled change to the IP addresses for one of the authorities listed for the DNS root zone and the .ARPA TLD. The change is to H.ROOT-SERVERS.NET, which is administered by the U.S. Army Research Laboratory.

The new IPv4 address for this authority is

The new IPv6 address for the authority is 2001:500:1::53.

This change is anticipated to be implemented in the root zone on 1 December 2015, however the new addresses are operational now. They will replace the previous IP addresses of and 2001:500:1::803f:235 (also previously known as AOS.BRL.MIL and AOS.ARL.ARMY.MIL).

We encourage operators of DNS infrastructure to update any references to the old IP addresses and replace them with the new addresses. In particular, many DNS resolvers have a DNS root "hints" file. This should be updated with the new IP addresses.

New hints files will be available at the following URLs once the change has been formally executed on December 1:

The old IPv4 address will continue to work for six months after the transition (until 1 June 2016), at which point it will be retired from service. The address will remain under the control of the Army Research Laboratory, never to be used again for DNS service. The old IPv6 address will continue to work indefinitely, but may ultimately be retired from service.

Simultaneous to the retirement of the old address on June 1, 2016, the ASN for H-root will change from 13 to 1508.

You can monitor the transition of queries to the new addresses at the following URL: