## DoH prevalence - as a prerequisite for ECH deployment - need ECH config (the key), from DNS, which then should be encrypted to not leak this config - you need config information through encrypted channels: so we want more DoH - Mozilla trusted resolver program: contracts with companies (data "rules" are stronger than GDPR) - partner types: - regional default: used by default in region/country - cloudflare in us and others - something else in, e.g., Canada - DoH can be disabled using canary domain, this is used by Rogers in Canada -> cannot do encrypted DNS at all - other heuristics for disabling DoH: custom CA cert in root store - Chrome does "opportunistic" DoH, might implement in FF as well - more ECH without DoH: get config in some other way - outer SNI in ECH well known, thus, easy to block - DoH is faster than DNS53 if well configured, due to long-lived connections (400s for CF), which ammortize the handshake overhead - this does not hold for Android: DoH on Android in the US is slower than Desktop users - down to cellular infrastructure, low-end devices, other stuff going on with the device - Make it harder to block ECH - put something different in the outer SNI, but then you can still IP block (blocking all of a CDN likely too disruptive, blast radius too big) - using as few IPs as possible means running out of port numbers, but apparently there is some solution to this - ECH data available over BigQuery for anyone ## MASQUE - Recap of how Connect-udp works - Fairness of different inner flows - Should http/3 really be the narrow waist - Facebook's webrtc attack ## L4S - History of L4S and ideas behind it