In this simplified diagram, you can see six autonomous systems on the Internet and two possible routes that one packet can use to go from Start to End. Our learning center has a good overview of what BGP and ASNs are and how they work.
#Fa ebook how to
Every ASN needs to announce its prefix routes to the Internet using BGP otherwise, no one will know how to connect and where to find us. An AS can originate prefixes (say that they control a group of IP addresses), as well as transit prefixes (say they know how to reach specific groups of IP addresses).Ĭloudflare's ASN is AS13335. An Autonomous System (AS) is an individual network with a unified internal routing policy. The individual networks each have an ASN: an Autonomous System Number. As we write Facebook is not advertising its presence, ISPs and other networks can’t find Facebook’s network and so it is unavailable. BGP allows one network (say Facebook) to advertise its presence to other networks that form the Internet. The Internet is literally a network of networks, and it’s bound together by BGP. Without BGP, the Internet routers wouldn't know what to do, and the Internet wouldn't work. The big routers that make the Internet work have huge, constantly updated lists of the possible routes that can be used to deliver every network packet to their final destinations. It's a mechanism to exchange routing information between autonomous systems (AS) on the Internet. Meet BGPīGP stands for Border Gateway Protocol. You can read that post for the inside view and this post for the outside view. That cascaded into Facebook and other properties disappearing and staff internal to Facebook having difficulty getting service going again.įacebook posted a further blog post with a lot more detail about what happened. Externally, we saw the BGP and DNS problems outlined in this post but the problem actually began with a configuration change that affected the entire internal backbone.
#Fa ebook update
How's that even possible? Update from Facebookįacebook has now published a blog post giving some details of what happened internally. This wasn't a DNS issue itself, but failing DNS was the first symptom we'd seen of a larger Facebook outage. It was as if someone had "pulled the cables" from their data centers all at once and disconnected them from the Internet. Their DNS names stopped resolving, and their infrastructure IPs were unreachable. Facebook and its affiliated services WhatsApp and Instagram were, in fact, all down.
Social media quickly burst into flames, reporting what our engineers rapidly confirmed too. But as we were about to post on our public status page we realized something else more serious was going on. Today at 15:51 UTC, we opened an internal incident entitled "Facebook DNS lookup returning SERVFAIL" because we were worried that something was wrong with our DNS resolver 1.1.1.1. “Facebook can't be down, can it?”, we thought, for a second. This post is also available in 简体中文, 繁體中文, 日本語, 한국어, Deutsch, Français, Español, Português, Pусский, and Italiano.