The closest to a VPN P2P-based solution that I have found is PeerVPN: really easy to install, but it needs to open one port (7000 TCP by default) on one of the computers (also known as node) that runs it.  I would like to prepare some Linux devices to automatically connect to any specific VPN network, for example by using some cron task, in order to find them remotely wherever they are. I have no access to the router(s), so I can not open ports.  The optimal solution would be some tool like:# p2pvpn --connect --network MyNetworkName$ ifconfigeth0      Link encap:Ethernet  direccinHW 00:23:54:7f:f2:4f          Direc. inet:192.168.11.113  Difus.:192.168.11.255 Msc:255.255.255.0tun0      Link encap:UNSPEC  direccinHW 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00          Direc. inet:10.8.0.6  P-t-P:10.8.0.5  Msc:255.255.255.255Note the tun0 newly created virtual interface. Is there anything like this?  Command-line solutions preferred.Multi-platform solutions preferred.Additional points:- Similar solutions (still require port(s) opening) are programs like OpenVPN (nearly a headache to setup, but working great).
Is there any P2P VPN solution that does not require port opening(forwarding)?
networking;vpn