a248.e.akamai.net is the name of a server that belongs to a company called Akamai. Akamai, while unfamiliar to most Internet users, serves between 10 and 20 percent of all web traffic. The company operates a vast network of servers around the world and rents space on these servers to customers who want their websites to work faster. Rather than serving content from their own computers in centralized data centers, Akamai's customers can distribute content from locations close to every user. When a user goes to, say, Whitehouse.gov, their computer is silently redirected to one of Akamai's copies of the Whitehouse website. Often, the user will receive the web page much more quickly than if they had connected directly to the Whitehouse servers. And although Akamai's network delivers more 650 gigabits of data per second around the world, it is almost entirely invisible to the vast majority of its users. Nearly anyone reading this uses Akamai repeatedly throughout the day and never realizes it. Except when Akamai doesn't work.
Akamai is an invisible Internet intermediary on a massive scale. But because SSL is designed to detect and highlight hidden intermediaries, Akamai has struggled to make SSL work with their service. Although Akamai offers a service designed to let their customers use Akamai's service with SSL, many customers do not take advantage of this. The result is that SSL remains one place where, through error messages like the one shown above, Akamai's normally hidden network is thrust into view. An attempt to connect to a popular website over SSL will often reveal Akamai. The White House is hardly the only victim; Microsoft's Bing search engine launched with an identical SSL error revealing Akamai's behind-the-scenes role. "