How to combine several places into one network?

Question

VPN

It is necessary to combine a house, apartment, office and mobile into one network. phones. Tell me how to do it right?
The house has a dedicated IP with wired internet from a local provider. The speed is 4 MB according to the tariff, in fact, about 1 MB. The apartment has the same provider, without a dedicated IP. In the office and on 4G mobile phones.
The house and apartment have video surveillance. The office has a file server. It is necessary that from any point there is access to both viewing video surveillance and the file server. You can connect to the house using its IP, but the rest of the IP points are "gray".
Will a VPN server in the house help in this case so that everyone else clings to it?
Will it be possible to watch video surveillance through vpn?
And how to secure a dedicated IP so that no one breaks into it?
added: Linux on all PCs.

Answer 1

as an option Mikrotik on it to raise an L2TP server with encryption, video viewing is possible, but it will slow down, it all depends on the workload of your 1mb, it is possible that the outgoing speed at your home will be higher.