We were the lucky targets of China's DNS poisoning on Monday the 19th. Any requests from clients in China to Edgecast's CDN was instead thrown at our public IP. After deducing what was going on, we ended up blacklisting large (class A in some cases) APNIC address blocks assigned to China.

Interestingly, it wasn't our webservers that were overwhelmed but instead the Cisco firewall that sits in front of them. 25K concurrent connections made it decidedly unhappy.