I have a mobile data plan of 2 GBs. When I exceed it, I always get redirected to the network operator's website when I trying to load an URL. For some reason Telegram(Android app only, Desktop app doesn't go through) works without any problem or restriction. I can send and receive texts, audio messages and pictures.
My question is how does Telegam (or a similar app) goes through the block.
When inspecting Chrome Dev. console's network tab every website throws an
HTTP 302 Moved Temporarily status code, and I get redirected to the network OP's site. I verified that Telegram works on HTTP 1.1/TCP port 80.
Additionally, is it a bug in network op's software? Is it legal to use although my data plan is exceeded? I'm curious.
The browsing and traffic of other apps are totally blocked, so it's not about that my data plan just got slowed down. And in my country there is no law for enabling some data traffic for emergency text, at least not over data plan. Also my network operator hasn't advertised free network traffic for Telegram, like other network operators for facebook or etc..
I tried reviewing my network traffic with Wireshark but there was no main difference in the packets of Telegram and Chrome's packets. I also started to search after some connection techniques in Telegram's code(it's on github) but it has a really huge code base.
I also noticed this behavior with Skype last year, but now it doesn't seem to connect.