How GRE Works | VPN Tunnels | Computer Networking | Part 1 Have you ever wondered “How does a GRE Tunnel work?” “How do I encrypt GRE” “What are the best practices for improving GRE Stability?” If you answered yes to any of these questions, then this series is for you! #GRE (Generic Routing Encapsulation) tunnels are one of the most versatile tools available to a network engineer. They are a #VPN that can be used to tunnel through the internet, create virtual site to site WAN’s, bypass networks, run routing protocols like OSPF, EIGRP, and BGP, avoid RIP hop count issues, migrate to IPv6, and connect to DDoS scrubbers. A pair of routers will build a tunnel between VTI’s (Virtual Tunnel Interfaces). This passes through a network called the underlay network. The underlay is transparent to traffic passing through the tunnel. The tunnel is the overlay network. GRE added extra headers to the original packet. This leaves the original packet untouched while the encapsulated packet travels through the underlay. Remember to watch out for MTU and MSS! Try it yourself in the lab! https://networkdirection.net/labsandquizzes/labs/lab-gre-tunnels/ GRE TUNNELS SERIES Part 1: How GRE Works - See the encapsulation process, as a packet moves from one side of the network to another - https://www.youtube.com/watch?v=ytAqv7qHGyU 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 – coming September 7th 2018 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 – coming September 21st 2018 Thanks for watching Network Direction! Be sure not to miss out on Part 2 and 3 of our GRE Tunnel Series by subscribing here: https://goo.gl/Z9bk72 For more information, have a look at https://networkdirection.net/GRE+Tunnels This video is useful for #Cisco #CCNA and #CCNP certifications Be sure to check out our other Networking videos: VxLAN Series: https://goo.gl/RjDuya Network Direction Official Playlist: https://goo.gl/QGikwC LET'S CONNECT 🌏 null 🌏 https://twitter.com/NetwrkDirection 🌏 https://www.patreon.com/NetworkDirection 🌏 https://www.facebook.com/networkdirection 🌏 https://www.networkdirection.net/