A company statement blamed the problem on the actions of a single technician, leaving some observers dismayed that the world's biggest software company could have organised its network so inadequately.
Microsoft's Web site could not be reached using ordinary text URLs between 3.30am on Wednesday morning and 2am the following day. However, the company's Web servers were still functioning properly and could be reached using numeric IP addresses.
Microsoft said one of its technicians had changed the configuration of routers on the edge of the company's Domain Name Server network (DNS servers are used to connect text-based domain names with the numeric addresses of the servers they refer to). This alteration impaired communication between the company's DNS servers and other DNS servers on the Internet.
After reading the Microsoft statement, a senior network engineer at Computer Sciences Corporation said, "It seems odd that the change control policies and management systems in place at Microsoft would allow a single technician this level of control without a sign-off procedure."
IDC analyst Dan Kusnetzky agreed, "We have to take it as read that what Microsoft claims happened did, but it is still incredibly embarrassing for a company with such knowledge of Web enterprise to be affected in such a way. A well-designed Internet infrastructure should not have suffered like this."
In its statement Microsoft stressed: "This was an operational error and not the result of any issue with Microsoft or third-party products, nor the security of our networks."