When SNIs Cannot be Trusted
SNI (Server Name Indication) is an optional extension in TLS/QUIC that contains the symbolic host name we’re connecting to. For instance, during the TLS handshake, the SNI allows the server to identify the correct TLS certificate of a server hosting multiple websites. nDPI reports SNIs in order to make it possible to detect name-based services deployed on the same server IP address. Below you can see an example of how nDPI reports SNIs in encrypted traffic. Client applications use the SNI to verify that the website it is connecting to matches …