There are ton of threads at this forum talking about some kind of opensource/linux base Arduino TCP/IP shield.
OpenWRT is not
an Arduino TCP/IP shield but an operating system for a WiFi access point/router.
Raspberry Pi is complete ARM-PC with a Linux operating system and also not an Arduino shield.
build in at above shield, one command to turn, one to turn off.
None of that list is an Arduino shield.
I do those thing all the time however only for test purpose, and not for Arduino, for some thing else. I am not supposed to do that. but I have root password. Ok you tell me what else make it available on the Internet?
I just told that putting it into a DM zone is not sufficient
to make it available on the public Internet.
4. Arduino isn't able to do SSH let alone SSH tunneling.
either build in or one command to install, need modify config file since we need Reverse SSH Tunneling not standard SSH Tunneling.
5. Arduino isn't able to do VPN
one command to install, one on, one off.
I get the impresion, you have absolutely no clue about what an Arduino is. An embedded Linux box is not