As far is i know they got a pretty damn sophisticated monitoring and filtering systems built by Nokia and Siemens which allows them stuff like deep packet filtering and voice recognition through the mobile networks…
It’s kind of funny when you think about all these sanctions which go from medicine to other industrial goods but stuff like that is openly sold to Iran without anyone bitching about it, how can that be!?
Other than that the Iranians have their workarounds to pass through the filters. It’s so common that even my 62 year old aunt helped me out to set up tor on my mac :D
