MTProto-proxy works only with Telegram. The client and server do not have an open communication phase. In the Telegram MTProto-proxy server implementation, the proxy server and its owner do not have direct access to the MTProto protocol meta-information (logins, for example).
For all sorts of filters and analyzers, the exchange of data with the MTProto-proxy server looks like an unstructured binary bi-directional data flow between the client and the server. This makes it difficult to recognize the protocol for the purpose of limiting.
22 february, 2020
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