Meet Gatebot – a bot that allows us to sleep
In the past, we’ve spoken about how Cloudflare is architected to sustain the largest DDoS attacks. During traffic surges we spread the traffic across a very large number of edge servers. This architecture allows us to avoid having a single choke point because the traffic gets distributed externally across multiple datacenters and internally across multiple servers. We do that by employing Anycast and ECMP.
We don't use separate scrubbing boxes or specialized hardware - every one of our edge servers can perform advanced traffic filtering if the need arises. This allows us to scale up our DDoS capacity as we grow. Each of the new servers we add to our datacenters increases our maximum theoretical DDoS “scrubbing” power. It also scales down nicely - in smaller datacenters we don't have to overinvest in expensive dedicated hardware.
During normal operations our attitude to attacks is rather pragmatic. Since the inbound traffic is distributed across hundreds of servers we can survive periodic spikes and small attacks without doing anything. Vanilla Linux is remarkably resilient against unexpected network events. This is especially true since kernel 4.4 when the performance of SYN cookies was greatly improved.
But at some point, malicious traffic volume Continue reading