We currently have four Windows 8.1 and 10 computers on a small network. We're looking for a way to occasionally connect to the network from home/abroad with two users, each with their own laptops, possibly behind their own NAT. Our network is set up as a workgroup, not a domain, and the central server is on Windows 8.1. We're on a NAT, which is managed by a business incubator that we're in, and has a static IP facing the internet. We probably can get the folks who run that NAT to forward a random high numbered port to one of our machines.
We're looking for a VPN server and client solution which will work in the above case, and:
is free or reasonably priced for business use. e.g. <£100 or <£5pcm
is easy to set up, ideally a GUI or simple config files. Bonus points if the clients don't need any software installed.
is nice and secure:
a) Uses a good, proven communications protocol
b) Rarely has major bugs/exploits (as far as this can be known) and/or is easy to keep up to date.
c) Is easy for me to configure right, and hard for me to mess up, even though I've never set up a VPN before.
What I've found so far:
Windows "Incoming Connection" feature: Built in to all versions of windows. Seems to use some form of antiquated protocol, and the general consensus from google is that it is not, and cannot be made, secure.
Microsoft SSTP: Looks easy, clients built into windows, but seems to need Windows Server on the server, which we don't have.
OpenVPN Looks popular and well regarded, but the setup process doesn't look easy. Especially so on the clients.
SoftEther Looks friendly and easy to use, but doesn't seem to have the pedigree of the other options. The website and documentation doesn't look as polished and convincing.
Remote desktop: Not quite a VPN as such, but we could just forward an external port to the remote desktop port. We could then remote into other machines from there and copy files. Copying files is slow, and network shares wouldn't work.
Teamviewer: Also not quite a VPN, but very easy to use and doesn't need port forwarding set up. Too expensive to justify for occasional use, and I don't think we could set up network shares.