Why Did Facebook Go Down?

At around 10am ET on October 4 2021, people started noticing something weird: they weren’t getting any new content on their Facebook and Instagram feeds. Their Whatsapp messages stopped going through. They went to Facebook.com directly on their browser and it wouldn’t connect.

“Is my internet down?” People wondered. But it wasn’t their internet, or even the internet, which was fine at the moment. So what went wrong?

Internet communication seems seamless to the end user, but in reality, every bit of data you transmit has to be passed along to its destination. First it goes to your router, which then passes it along to the next router closer to its destination, which in turn passes it along, again and again until it gets to its destination. This is how routing, the cornerstone of networking, works.

Routers know the most efficient route to pass your traffic along because they talk to each other. Your traffic goes through a lot of different unrelated routers before ending up at one of Facebook’s, and it gets to them because each router along the way has advertised that it’s 1 step closer to Facebook.

This is usually a very efficient system. But what happens when all of Facebook’s routers simultaneously tell the rest of the internet that they’re no longer able to pass any traffic along?

All of a sudden, nothing can get to Facebook. Your home network might know exactly where Facebook.com is, but the path to get there has a big hole in it that it can’t go around, because Facebook’s own routers handle the last step of getting any traffic directly to Facebook.

So you and two billion other people refresh Facebook and get a message that the site can’t be reached for hours on end, causing panic and a major stock dip – all because of one small configuration change.

Who handles your networking and what’s your continuity plan? Call eIRONclad at 858.202.1758 for a no-obligation assessment of your risk and potential downtime in the case of a networking problem. Don’t wait until it’s already happened to you to figure out your recovery plan.