Network service provider Cloudflare recently detailed, in a blog post, an incident that centered around a Border Gateway Protocol (BGP) route leak. This incident unfolded over a 25 - minute period and had a notable impact on IPv6 traffic. It led to congestion on the Miami backbone link, a situation where data struggled to flow smoothly through this crucial network artery. For some customer traffic, there was either packet loss, meaning that some data packets failed to reach their intended destinations, or increased latency, causing delays in data transmission. Additionally, the incident resulted in the loss of approximately 12 Gbps of external network traffic. This traffic was discarded due to firewall filtering rules, which acted as a barrier and prevented the data from passing through as intended.

The root cause of this incident can be traced back to a misconfiguration in the automated routing policy of a router located at one of Cloudflare's data centers in Miami, USA. This router mistakenly announced IPv6 BGP prefixes. These prefixes were originally meant solely for internal propagation within Cloudflare's network. However, due to the misconfiguration, they were inadvertently made available to external networks, ultimately leading to the BGP route leak.