SnapGear 2.0.1 - Manual (Page 160)

Virtual Private Networking
156
Troubleshooting
•
Symptom: Cannot ping a host on the other side of the GRE tunnel.
Ensure that there is a route set up on the GRE tunnel to the remote network.
Ensure that there is a route on the remote GRE endpoint to the network at this end of
the GRE tunnel.
Check that there is a GRE interface created on the device. To do this, go into
Advanced Networking and scroll to the bottom. There should be an interface called
greX created. greX is the same as the Interface Name specified in the table of
current GRE tunnels.
Also ensure that the required routes have been set up on the GRE interface. This
might not occur if you have the same route specified on different GRE tunnels, or on
different network interfaces.
Ensure that the remote GRE endpoint is reacheable. Do this by using the ping utility
on the Advanced Networking page.
•
Symptom: Cannot ping the remote GRE end point.
Ensure that the remote GRE end point responds to pings. Note that by default no
packets will be routed across the GRE tunnel unless there is a route setup on the
GRE tunnel.