"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.