AMSTERDAM -- Microsoft Corp. confirmed Wednesday that most of its online properties became unreachable Wednesday morning due to a problem in the system that maps Web addresses to IP (Internet Protocol) addresses.
Sites hit include Web-based e-mail service Hotmail.com, Web portal MSN.com, news Web site MSNBC.com and the company's corporate site Microsoft.com.
"The Internet's Domain Name System (DNS) does not return the correct response when it is queried for a Microsoft Web site," said Ruud de Jonge, support manager at Microsoft Benelux.
The first reports of the problem started coming in "very early" Wednesday morning, said De Jonge. It is unclear when the sites will be available again. "It will take some time, this can't be restored by hitting one switch," he said.
Microsoft has yet to pin down the cause of the DNS error. "It can be a system or human error, but somebody could also have done this intentionally," De Jonge said. "We don't manage the DNS ourselves, it is a system controlled by the Internet Corporation for Assigned Names and Numbers (ICANN) with worldwide replicas."
A team at Microsoft's headquarters in Redmond, Washington is working on the problem, which has been given top priority, said De Jonge.
Because of the blackout, some 60 million Hotmail users worldwide can't access their e-mail, Microsoft customers can't download software updates or get online support and MSNBC.com has no audience. Other services that can't be reached include Windowsupdate.com, which contains updates for the Windows operating system, Passport.com, Microsoft's online identification service, and bCentral.com, a portal for small and medium sized businesses.
Hackers could be responsible for the outage that has continued for hours now, said Simon Hania, spokesman for Dutch Internet service provider XS4ALL Internet BV. "The name server that is authoritative for Microsoft's Web sites might have crippled under a Denial of Service attack," he said.
Hania said, however, it is more likely that a network error or system failure caused the problem.
The DNS consists of many machines around the world set up in a hierarchy. "It looks like the machine hit is in the top of the DNS tree," Hania said. "Once it is fixed it can take a couple of hours for all DNS systems around the world to pick up the correct DNS information."
Microsoft, in Redmond, Washington, can be reached at +1-425-882-8080 or at http://www.microsoft.com/.