In order to properly proxy messenger apps from censored networks to outside, I added the -X switch to crash and documented on how you would configure your setup within the contrib folder.
It is already field-tested in certain countries. Nevertheless, if you have deeper knowledge on censorship equipement or extra tips for better connectivity and can battle test the setups, just let me know.
I re-polished a 10y old project that is one of the most complete tunneling solutions available for ICMP, ICMPv6, DNS over IP and DNS over IPv6 when it comes to setting up connectivity in restrictive environments. I added some fixes so it now properly also works behind NAT.