A networking problem made Yahoo's Web site unreachable for many users in the US and Canada yesterday (3 December).
The problem, first observed at around 11:40 a.m. Pacific Time, appears to have primarily affected users in the eastern United States and Canada who were trying to reach the www.yahoo.com domain.
Network engineers on the NANOG (North American Network Operators Group) discussion list reported that when they tried to reach www.yahoo.com, they were sent on the Internet's version of a wild goose chase.
DNS (Domain Name System) servers redirected traffic to another Yahoo domain, www.wa1.b.yahoo.com, which was not associated with an IP address.
In other words, computers trying to find Yahoo's Web site were sent nowhere.
The problem appeared to have been resolved by about 1 p.m. Pacific Time.
Yahoo did not have much to say about the outage. The company confirmed in a statement that it had "a disruption in service earlier today that affected users in some geographic areas."
One NANOG poster, apparently a Yahoo employee named Matthew Petach, reported that the problem was triggered by a Juniper T1600 router that "went kablooie."
"This is primarily affecting traffic coming through Ashburn, Virginia," Petach wrote at 1:16 p.m. Pacific Time.
"We're aware of the issue and have put workarounds in place; you should be back up and functional for the moment, though not in an optimal state."
The kind of router failure described by Petach could easily have accounted for the problems reported on NANOG Wednesday, if Yahoo's DNS nameservers were behind that faulty router, said Cricket Liu, vice president of architecture with DNS appliance vendor Infoblox.
Yahoo appeared to have fixed the problem by moving some of its DNS services to nameservers run by Akamai, a company that helps sites deliver Web content, Liu said.
"It sounds like maybe they changed ... to Akamai to save their network bacon," he said.