

Size and timing of packets. Protocols generally have consistent patterns, so say always 6 packets with the last 3/4ths filled. Then some keepalive at regular intervals (i.e. tracker updates), establising new peer connections, …
Luckily this deep inspection is illegal for isps in the eu.
Russia, China, and Iran are using the patterns to effectively block all normal VPN and proxy protocols. There, people need special tools that send fake packets, randomize timing, and split and group packets into different sizes. All of course decreasing speed and increasing latency.
For UDP you’d also usually reencode packets as http3 warp ones so it looks like a video call.
Then the other end needs the same tooling to restore the normal packets.
Obfuscating it would be possible if necessary, but it’s better when you aren’t forced to maintain such an obfuscation stack.




Sorry I probably meant QUIC not warp. It is related, I think webrtc now usually uses quic, so masking as quic or webrtc are probably synonymous, but honestly I don’t know enough about the details to say for sure.
I know people in Russia are reporting Mullvad gets fully blocked, so I don’t think DAITA is enough. As @chimp@lemmy.dbzer0.com mentioned, Hysteria is more in the right direction, though in more modern iterations/forks and together with another layer of obfuscation.
I don’t generally like to shout out names too much, since popularity among those that don’t need the tools makes them more cracked down upon for people that do need them. So I’ll just say that for the less obfuscated but more responsive route via rtc you use an updated hysteria as the outer layer, containing a fully homogeneous encrypted stream from a tool named after a reptile.
Mainly Net neutrality rules. Net neutrality just barely allows basic DPI, though it already heavily restricts what ISPs can actually do with that inspection. Wikipedia: EU net neutrality violations. Note that the 2007 case there happened well before regulations were strictened.