Deep packet inspection (DPI) hardware can identify an astonishing array of protocols passing across the Internet‚Äîup to and including protocols that are rare even to us in the Orbiting HQ (Gadu-Gadu? Manolito? Feidian?).
There are a lot of bogus VPN (virtual private network) products sold for big bucks that are not real VPNs at all, but SSL portals. OpenVPN is a genuine secure VPN that supports both site-to-site tunnels, to create a nice secure WAN on the cheap, and remote individual clients.