dê uma olhada em StrongSwan . De acordo com o seu wiki , ele deve ser compatível com o Windows 7:
Windows 7 fully supports the IKEv2 (RFC 4306) and MOBIKE (RFC 4555) standards through Microsoft's Agile VPN functionality and is therefore able to interoperate with a strongSwan VPN gateway using these protocols. strongSwan currently can authenticate Windows 7 clients either on the basis of X.509 Machine Certificates using RSA signatures (case A) or Username/Password using EAP-MSCHAP v2 (case B).