On Thu, Oct 7, 2021 at 10:23 AM Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp> wrote:
William Herrin wrote:
Facebook's _internal_ DNS, while not anycasted, followed a similar logic: if the data center is isolated and their data goes stale, they stop serving potentially wrong answers.
As I already wrote, that is a standard mechanism of DNS with SOA expiration period as is documented in rfc1034
Then we agree: The failure mode was that after the data centers disconnected from each other, all their DNS expired, breaking the tools they'd normally use to recover. Facebook withdrawing the BGP routes to its anycasted public DNS servers as they expired made no difference. Regards, Bill Herrin -- William Herrin bill@herrin.us https://bill.herrin.us/