On 2020-07-30, iyouportreported (archive) the apparent blocking of TLS connections with the encrypted SNI (ESNI) extension in China. iyouport says that the first occurrence of blocking was one day earlier, on 2020-07-29. We confirm that the Great Firewall (GFW) of China has recently begun blocking ESNI—one of the foundational features of TLS 1.3 and HTTPS. We empirically demonstrate what triggers this censorship and how long residual censorship lasts. We also present several evasion strateg...
