GRE Encryption with IPSec | VPN Tunnels Part 2 GRE tunnels do not have any native encryption! Fortunately, you can add IPSec encryption in transport mode to your tunnel. First, we’ll have a quick look at how IPSec works. IPSec uses two security tunnels (called phase-1 and phase-2) for authentication, cipher and hash proposal, and session key exchange. Some of the protocols used in this process include ESP (Encapsulating Security Payload), IKE (Internet Key Exchange), ISAKMP, AH (Authentication Header), and the Diffie-Hellman algorithm. Once both sides agree on how these protocols will work, they will have built an SA (Security Association) If you have NAT in your network, IPSec can detect and work around it with NAT-T Try it yourself in the lab! https://networkdirection.net/labsandquizzes/labs/lab-gre-tunnels/ Part 1: How GRE Works - See the encapsulation process, as a packet moves from one side of the network to another Part 2: GRE Encryption with IPSec - GRE is not encrypted by default! See the basics of IPSec, and how we can use it with GRE tunnels Part 3: Improving GRE Stability - There are a few pitfalls to watch out for, including recursive routing. See some of the best practices that you can apply to make your tunnel stable For more information, have a look at https://networkdirection.net/Advanced+GRE This video is useful for Cisco #CCNA and #CCNP certifications 🌏 null 🌏 https://twitter.com/NetwrkDirection 🌏 https://www.patreon.com/NetworkDirection 🌏 https://www.facebook.com/networkdirection 🌏 https://www.networkdirection.net/