GRE Tunnels: A Step By Step Configuration Guide

Want to configure a GRE Tunnel with ease? Then this video is for you.
In this video, you will learn every configuration step needed to configuring a GRE Tunnel between 2 Cisco Routers.
What you will learn first is the basic requirement of two routers forming a GRE Tunnel, which is basic IP Connectivity. We will discuss how this connectivity is established.
After we cover basic IP Connectivity, we go step by step and configure a GRE Tunnel on two Cisco Routers. We will then cover how you can verify that the tunnel is UP and working as designed.
Next, I will show you how you can configure routing that will allow your two routers to route traffic between each other over the tunnel that was formed. You can use Static Routing or a Dynamic Routing Protocol, and I will show you both ways.
From here, I will explain what can lead to a Recursive Lookup Failure with GRE Tunnels, and how this can lead to your GRE Tunnel not working properly if you run into this situation.
And finally, we will take a look at a packet capture so you can see exactly how the GRE Encapsulation is done when traffic is being routed over a GRE Tunnel.
I hope this video helps you become more confident in configuring GRE Tunnels.
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0:15 - What is required to form a GRE Tunnel between two routers
2:45 - GRE Tunnel Interface Configuration
9:25 - Configuring the loop back interfaces for verification
10:30 - Static Routing over the GRE Tunnel
13:25 - OSPF Routing over the GRE Tunnel
17:15 - Recursive Lookup Failure with GRE Tunnels
20:25 - Packet Capture of GRE Encapsulation

[@mosesa.4336]

You did a great job explaining GRE. Good job!

[@adrianmxmx]

Excellent Content

[@adrianmxmx]

Hope you do some EEM too. I am setting up a real word situation:
CE1 and CE2
CE1 has DIA and CE2 has DIA and a 4G last resort.
If both DIA's fail, there are EEM scripts to enable the 4G link.
Love to see your thoughts too on real world practical applications.
Great content and keep it up Bro.

[@ciscenius]

I'm not good with EEM scripts, but we used them at one of my old jobs. We had two edge routers each having BGP connecting to the ISP. These were our internet routers. We had SLAs configured on each router to verify if the connection was good. If all the SLAs failed, we knew something was weong with the circuit. If BGP was still up, we didn't want to prefer the ISP. So a script was in place to replace the route-map with another route-map that would make that peer less preferred. So no traffc would go in or out of that peer. I'll definitly do a video on it

[@electronicparadiseonline2103]

New to the channel. Great Content!!! Do you have a CCNP Routing and Switching Cert. If not, what do you think about the CCNP Routing and Switching Cert?

[@ciscenius]

The Routing & Switching cert went away last year and was replaced with the CCNP Enterprise. I do have that cert and if your really want to make money, you need it. It’s the one cert that will put you into the Senior roles

[@MarkMiller-vo6yp]

I am trying to setup a VPN with an RV340 at HQ and an RV325 at a remote site. The remote site is behind a router without a public IP. Is there anyway to make a VPN work like this? I was thinking the GRE Tunnel would help do this and then do IPSEC inside that tunnel. I was having trouble getting the initiation to start from the remote site and can't seem to get it to work. Once the tunnel showed up but did not pass any traffic. I have configured other VPNs using Sonicwalls which seem to address this problem automatically.

[@adrianmxmx]

Whomever gave a down is a clown 😜