On 10/7/21 00:22, Michael Thomas wrote:
But it wasn't just their DNS subnets that were pulled, I thought. I'm obviously really confused. Anycast to a DNS server makes sense that they'd pull out if they couldn't contact the backend. But I thought that almost all of their routes to the backend were pulled? That is, the DFZ was emptied of FB routes.
During the outage, we kept serving traffic to Facebook in various locations. So it would seem that while a large amount of their NLRI left the DFZ, it wasn't all of them.
However, what was left was not sufficient to actually keep typical services up, including their DNS.
Mark.
