How to replace TeamViewer?

Question

VNC

The task is next.
1. You need the ability to access (control) simultaneously from two devices.
2. There is no real IP on the managed computer and on the router behind which it stands.
3. Clients - Windows, iOS.
4. The managed computer can reboot at any time.
5. Get the result for free or for a one-time payment up to $20. No usage time limits as it happens in TeamViewer.
Thank you.

Answer 1

As an option - LiteManager. It is free, there is support for different operating systems, it is sharpened for administration ... In general, like that camel, out of 3 heroes, "fast, hardy and hardly eats" (c). www.litemanager.ru
The scheme there is as follows:
On a "managed" machine - a server. A module that is launched together with the machine and gives access to the "viewer" by a unique ID.
On the "manager" - the viewer. There connection, viewing and everything else.
On the same machine, of course, there can be both a server and a viewer.
Comparison of Free and Pro versions: www.litemanager.ru/produkts/LiteManagerFree
By the way, the Free version, that is, free aka for free, has been for 5 years already ... the functionality has been increasing, but the conditions for free (up to 30 machines and 3-4 minor additional functions have been cut) have not changed during this time. So, there is little hope that this is not only "for the time of promotion" ...

Answer 2

you can rent a real ip for not expensive
, etc. An alternative to Teamviewer for machines behind NAT with a gray IP?