2023-gfw-blocking-1111

The blocking of 1.1.1.1 in China, starting from 2023-10-01

Abstract

Documents the GFW's blocking of Cloudflare's 1.1.1.1 DNS resolver beginning October 2023, with implications for DoH/DoT-based bootstrapping mechanisms that defaulted to Cloudflare.

Team notes

Practical: 1.1.1.1 has been an unreliable DoH endpoint from CN since Oct 2023. Lantern's kindling library should not depend on 1.1.1.1 reachability for CN bootstrap. (Worth checking that we don't.)

Tags

censors
cn
techniques
ip-blockingdns-poisoning
defenses
dns-tunneling
method
measurement-study