Attached is a diagram and three router configurations. I am trying to build a gre tunnel from rtr3_ospf to rtr4_ospf.
My tunnel0 on both routers are down and I can not ping the remote address 192.168.0.0/30. Any assistance and insight into why it is not working would be greatly appreciated.
>> When I remove the keepalive 10 3, the tunnel comes up. I'm still not sure what I am doing wrong.
not all IOS images or platforms support GRE keepalive you may be using a release that allows you to configure it but it does not support it.
For example in real world you cannot use the above command on a C6500/C7600 they do not support it.
you are using GNS3 so you need to check if the loaded IOS image support GRE keepalive using feature navigator
Hope to help