Configuring a GRE over IPsec Tunnel Using the
SDM
The Site-to-Site VPN Wizard has an option for configuring a GRE over
IPsec VPN. It leads you through creating the tunnel interface and specifying
the parameters such as tunnel source and destination and interface IP
address. The wizard also leads you through creating an optional backup
GRE tunnel in case the primary one goes down.
Next, the IPsec parameters are presented. The wizard walks you through
creating an IKE policy and transform set. You can either use the ones
included with SDM or create new ones through the wizard.
You then have the option of configuring either static routing or the dynamic
routing protocols Enhanced Interior Gateway Routing Protocol (EIGRP) or
Open Shortest Path First (OSPF).
As before, the wizard shows a summary of the VPN configuration so that
you can review it before applying it by clicking Finish. You can test the
tunnel and monitor its status through SDM. Use the same show crypto and
debug commands shown earlier to verify and troubleshoot the VPN. In addition,
the show interfaces command shows the status of the logical tunnel
interface as the physical outgoing interface.