Hello.
It was a project I had in mind for several years, but every time I started it, it never ended up the way I wanted: a home VPN through the services offered by Windows.
The main problem was neither configuring a dynamic DNS (I had that for ages) nor the configuration of the VPN itself, but being able to reach it from outside (it works perfectly within the same network): in the countless guides I read about it, no one specified that the router must support VPN passthrough.
In the end, for this reason, reluctantly I had to resort to third-party software with an Android client.
“Hamachi,” unfortunately, doesn’t have an Android client that does what I want, so I opted for “OpenVPN.”
To configure it optimally, I recommend this excellent guide and reading all the HOWTO on the official website.
If everything goes smoothly, good for you: I had several problems, solved after searches on Google.
The first was with “build-ca.bat”: it returned “unable to write ‘random state’”.
To solve it, I followed the instructions written in this topic (specifically, this post).
The second problem I had was with folder sharing: services like VNC, FTP, etc. worked perfectly, but I couldn’t access the shared folders.
After two hours of research, reading guides, and experimentation, I hadn’t found the problem (and, therefore, not the solution either).
Having to do other things, I gave up for a few hours; when I returned, it took five minutes to find the problem and solution.
The problem was the Windows firewall: I don’t know why, but this time I didn’t consider it at all (usually it’s the first thing I think about).
The firewall blocks folder sharing if someone tries to access “from outside”: a quick search among the “ Well-known ports” on Wiki and… “Microsoft-DS Active Directory, Windows shares”, port 445 TCP.
Once this port is opened on the firewall, you’ll be able to access the folders.
Bye!
! :) !
PS: I haven’t given up: I’ll continue to search if it’s possible to “enable” a VPN through a router without VPN passthrough support.