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                    How Facebook Vanished from the Internet

   Josh Centers

   Around noon Eastern time on 4 October 2021, Facebook, Instagram, and
   WhatsApp suddenly vanished from the Internet and remained offline for
   much of the day. While no one outside Facebook yet knows why it
   happened, Internet infrastructure company [1]Cloudflare has an
   explanation of what went wrong. It all traces back to an obscure but
   vital networking protocol called the Border Gateway Protocol (BGP).

   BGP enables big networks to tell each other how to route packets. Early
   on 4 October 2021, BGP messages were sent that withdrew routes to
   Facebook's DNS servers, effectively taking them offline. DNS is short
   for Domain Name System, and it's the Internet protocol that lets you
   type tidbits.com to visit our site rather than having to know and enter
   our IP address of 172.67.213.57. Without global DNS servers knowing how
   to match facebook.com to an appropriate IP address, there was no way to
   connect to any Facebook server.

   Throughout the day, many other intermittent outages were reported, like
   Apple Pay, Gmail, and Twitter, along with cellular carriers, as you can
   see in the [2]Downdetector screenshot below. That likely happened
   because both apps and users kept trying to connect to Facebook, which
   strained the DNS servers and led to collateral issues all over the
   Internet. Facebook resolved the routing and lookup problems for its
   servers after about 5 hours, and Instagram came back an hour or so
   later.

   Cloudflare's blog post neatly summarizes the lesson from the day:

     Today's events are a gentle reminder that the Internet is a very
     complex and interdependent system of millions of systems and
     protocols working together. That trust, standardization, and
     cooperation between entities are at the center of making it work for
     almost five billion active users worldwide.

   [3]Read original article

References

   Visible links
   1. https://blog.cloudflare.com/october-2021-facebook-outage/
   2. https://downdetector.com/
   3. https://blog.cloudflare.com/october-2021-facebook-outage/

   Hidden links:
   4. https://tidbits.com/wp/../uploads/2021/10/Downdetector-Facebook-outage.png

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