Monday 11 April 2016 06.53 EDT Last modified on Tuesday 31 January 2017 10.58 EST. House of Cards star Kevin Spacey has said turning on the news makes him think the political thriller âdoesnât go far enoughâ in reflecting the real-life race for the White House.
For site-to-site virtual private networks (VPNs), the encapsulating protocol is usually IPSec or Generic Routing Encapsulation (GRE). GRE includes information on what type of packet you are encapsulating and information about the connection between the client and server.
A PPTP tunnel is instantiated by communication to the peer on TCP port 1723. This TCP connection is then used to initiate and manage a second GRE tunnel to the same peer. The PPTP GRE packet format is non standard, including an additional acknowledgement field replacing the typical routing field in the GRE header. However, as in a normal GRE connection, those modified GRE packets are directly encapsulated into IP packets, and seen as IP protocol number 47.