On July 7, 2005, NeuStar received a handful of reports that DNS resolvers were unable to resolve dotUS domains, plus the mention of the problem on the NANOG list. From the reports received, the DNS problem seemed to impact a limited number of independent organizations but was not widespread.
The reports followed a maintenance operation at one DNS site. During the maintenance operation a new piece of network equipment was installed. At approximately 10pm EDT (July 8 0200 UTC) the state of a previously operating load balancer was reset. At that time affected servers at independent sites resumed resolving dotUS names.
We have reviewed and revised our maintenance procedures to prevent a reoccurrence of this issue.