Last week October 4, Facebook services are down for 6 hours . According to Facebook this outage is not caused by any cyber attacks and main reason for the outage is due to the their BGP , this will show us a path to Facebook Data Centers.
Facebook Detailed about this incident caused due to one of regular maintenance , they mentioned that in order to check quality of global backbone capacity when they entered the command on machine and entire network connection is disconnected and Facebook also lost its connection to own Data Centers around the World. They also further mentioned that they have audit tool to stop these type of issue but due to bug it could not work properly.
These caused the BGP issue this is the protocol will advertise the DNS server IP address to rest of internet. while due to data Center disconnected BGP stop advertising this leads to entire outage around the world.
Facebook apologized for the outage and also they released the detail information about the outage.https://engineering.fb.com/2021/10/05/networking-traffic/outage-details/