Deep Packet Inspection (DPI) blocks Telegram by recognising the unique byte signatures of its transport protocol. Standard MTProto uses a fixed 0xEE prefix on the first packet and specific handshake patterns – easy for state-level filters like Russia's TSPU or Iran's DPI to match and drop. MTPr...
Source: [Dev.to](https://dev.to/humja_jaan_fca09049ae97d5/how-mtproto-obfuscation-and-faketls-defeat-deep-packet-inspection-4494)