I am using GNS3 to learn about GRE tunnels, I have it up and running on a serial connection over a T1. I do not have security setup on the tunnel. Both the tunnel and serial interfaces are up and I can ping back in-forth. My question is, besides looking at the tunnel interface is there a way to see if traffic is passing threw the tunnel. I can shut the GRE tunnel and everything still works. Plus I am not even sure the Tunnel is setup correctly. I have read many articles and this is still eluding me. thanks