How can I share files over the Internet?

Question

Computer networks

The point is this. Parents on the PC have files that are needed on the home PC.
Providers at home and at work are different. On the PC gray IP.
How can I share files? As an option of course hamachi or ftp ....

Answer 1

In order of decreasing speed:

1. A router with a white IP on one of the connections (VPN to it)
   
2. External server with white IP (VPN to it from both computers)
   
3. Programs for remote connection (TeamViewer, AnyDesk, Ammy Admin, etc.)
   

Answer 2

What about port forwarding on PC?

1. Connect to any STUN server (many public on the Internet).
2. Forward ports (UDP hole punching).
3. Write your protocol like TCP over UDP.
4. Transfer files.
As you can see, everything is quite simple.

Answer 3

Zerotier
The most, perhaps, the simplest option. Installed, connected computers to the network, forgot.
PS Zerotier itself does not share files, it only establishes a connection between computers (as if they were in the same local area - in fact, VPN), and what will you use next - standard Windows samba, ftp / http server, SSH or something more exotic - it's up to you