How to establish a stable connection with a device that has an unstable Internet connection and ports that are closed from the outside?

Question

linux

Internet via cellular networks is now very popular, so a lot of phones, tablets, laptops access the Internet via GPRS/3G/LTE networks. But the problem is that all Russian cellular communication providers close all ports, i.e. even if you are given a white IP address, then outside you will not reach this IP address in any way. Well, in addition to this - constant disconnects, reconnects and IP-address changes.
I constantly need to organize simple remote access to such devices, whether it be a phone, tablet, laptop or desktop computer. The simplest example is to dig deeper into the file system, download files, execute some commands in the console.
So that on any computer without installing special software, type something likeftp://[email protected] and access files, or ssh [email protected] and connect to the device console.
I have a Linux server with static IP addresses, I have already tried to organize communication through SSH tunnels - while the connection is stable there are no problems, but as soon as we catch a disconnect and change the IP address - I lose the device and I can’t for 10-20 minutes will connect to it. Well, after the reconnect, you have to start the session again.
What are the ways to organize such a connection that will work normally and not fall off during short-term disconnections, reconnects and changing the ip-address?

Answer 1

VPN connection to a gateway with a static IP

Answer 2

The concepts of "white IP" and "static white IP" for mobile operators are different. In the second case, a permanent IP is allocated, in the first - a free one. A static IP usually costs money, but ports are not blocked here.