During the morning of August 28, 2012 starting at approximately 02:34 PDT, an excessive amount of high PPS UDP traffic was directed at our Secondary DNS service for several hours. In response we activated remote triggered blackholes with our transit providers for the impacted IPv4 addresses. During this time we monitored our netflow data in an attempt to minimize disruptions to Secondary DNS. Only IPv4 was impacted, queries over IPv6 were uninterrupted. We apologize for the inconvenience.