As reported by DNSPod, One of China’s largest free DNS service providers, root name server of dotCN got attacked 5 hours ago, and lasted for 2 hours. During that time, most of the dotCN websites are unavailable. .com.cn was also attacked.
The issued time was from 01:10 AM local time, and basically recovered at 03:10 AM. Some service providers tried to enlarge TTL to reuse the DNS resolving records in cache servers. As for now, whois queries and DNS resolvings are still not full recovered for most of the websites:
$ whois 51tao.cn whois: cn.whois-servers.net: nodename nor servname provided, or not known
$ dig 51tao.cn ; <<>> DiG 9.8.3-P1 <<>> 51tao.cn ;; global options: +cmd ;; connection timed out; no servers could be reached
This is not the first time we faced this issue. Last time it occurred at 22th, March, 2013.
[Update] It has been officially confirmed that CNNIC was under extremely massive DDOS attack during that period. The attack lasted for several hours.