QuoteInternet Key Exchange (version 2) is an IPSec based tunneling protocol that was jointly developed by Microsoft and Cisco, and which is baked into Windows 7+. Technically speaking it (and the older IKE) is not a VPN protocol at all, but is a control protocol for IPSec key exchange. It is, however, regularly treated as a true VPN protocol, and it is convenient (and useful) to do so here.
