After an unprecedented 6 hour outage, Facebook has managed to restore functionality to its online properties, Facebook, WhatsApp and Instagram.

The issue was due to Facebook’s DNS service, which it runs internally, going down, and the problem not only caused massive disruption to the online lives of billions of people, but reportedly also made it impossible for many of their employees to enter their offices.

Facebook has made little comment regarding the issue, but will presumably post an autopsy of the incident at some point in the future.