Do you use Facebook, Instagram, or WhatsApp? You’re not alone. Recent numbers from statista.com show that Facebook has 2.89 billion monthly active users, Instagram is around one billion, and WhatsApp, the most popular global messenger app in the world, is around two billion. That’s a lot of people. If you’re reading this, chances are that you use at least one of the services.
Right around noon on Monday, October 4th, Facebook, Instagram, WhatsApp, and Messenger all went down. What could bring all the services down? For starters, Facebook owns Instagram, WhatsApp, and Messenger. All the services are connected by a backbone network that Facebook has built.
During what was meant to be routine maintenance, the company issued a command that was intended to assess the capacity of the global backbone network. This command ended up disconnecting Facebook from its backbone network, disconnecting Facebook data centers globally. The command resulted in the Facebook DNS servers becoming unreachable, which made it impossible for you or me to access Facebook.
What are DNS servers?
You’ve probably heard of DNS servers, but what are they? Every website has an IP address, and these numbers can be hard to remember. Brands use their name for the web address (i.e. www.facebook.com) because it is easier to remember. The domain name does not naturally work well with computers and network devices on their own when trying to locate one another. The IP address lets you know which server on the internet that the website is located on.
When you type in the domain address, the internet cannot automatically find the website you are looking for. DNS Servers are the translators between humans and computers. The DNS server sends out DNS queries to several servers, which each translate a different part of the domain you are trying to find. There are four different DNS servers queried, and they are:
- DNS recursive resolver
- The recursive resolver is the middleman between you and the name servers. When you hit enter and the recursive resolver receives a DNS query from a web client, it responds with cached data if available, or by sending requests to a root nameserver, TLD nameserver, and the authoritative nameserver. Once a response from the authoritative nameserver is received with the requested IP address, the recursive resolver sends the information to the web client and directs you to the website you are searching for.
- DNS root nameserver
- This is the first stop for the recursive resolver. There are 13 DNS root nameservers. When a DNS root nameserver receives the query from the recursive resolver, it responds by sending it to a TLD nameserver based on the extension of the domain.
- TLD nameserver
- TLD nameservers maintain information for all of the domains under a common extension. For instance, when you search for Facebook.com, your query will be sent to the TLD nameserver that contains all of the information for the ‘.com” websites. The TLD nameserver will then direct the query to the authoritative nameserver for that domain.
- Authoritative nameserver
- Typically the last stop on the quest for the recursive resolver, the authoritative nameserver contains all the information for the particular domain that it represents and will provide the IP address for the server, which is found in the DNS A record.
Now you have gained a plethora of DNS information that you never knew you wanted to know. The Facebook outage was caused by a command that unintentionally cut off Facebook from its DNS servers. Fun Fact, this resulted in the domain showing for sale on various marketplaces.
Whether your use Facebook and its various services at home, for business, or both, we were all without it for some time on Monday, October 4th. What did you do while it was down?