Fixing reachability to 1.1.1.1, GLOBALLY!

In March 2018, Cloudflare launched its fast and privacy-centric DNS resolver service with the IP address 1.1.1.1. However, they found that many Internet Service Providers (ISPs) and Customer Premises Equipment (CPEs) were misusing this IP address for their internal communication or blocking it due to legacy configurations. This resulted in a significant number of users being unable to access the DNS resolver service. To resolve these issues, Cloudflare collaborated with various ISPs and CPE manufacturers to clean up the bad routing globally. They also provided four IPs (two for each IP address family) to provide a path towards the DNS resolver independent of IPv4 or IPv6 reachability. By April 3, their efforts had increased the availability of 1.1.1.1 from around 91% in Europe and North America to 97%, and from 73% globally (excluding Europe and North America) to 85%. They continue to work with ISPs and CPE manufacturers to achieve their goal of making 1.1.1.1 properly routed and available for 100% of Internet users.