A syslog message from a router with a GRE tunnel reads: "%TUN-5-RECURDOWN: Tunnel0 temporarily disabled due to recursive routing". Which scenario would cause this error?
A. The remote router’s tunnel interface is not participating in the routing process.
B. The local tunnel mode does not match the tunnel mode configured on the remote router.
C. The shutdown command has been issued on the source physical interface.
D. The installed route to the tunnel destination has been learned via the tunnel interface.
The %TUN-5-RECURDOWN: Tunnel0 temporarily disabled due to recursive routing error message means that the generic routing encapsulation (GRE) tunnel router has discovered a recursive routing problem. This condition is usually due to one of these causes:
* A misconfiguration that causes the router to try to route to the tunnel destination address using the tunnel interface itself (recursive routing)
* A temporary instability caused by route flapping elsewhere in the network
https://www.cisco.com/c/en/us/support/docs/ip/enhanced-interior-gateway-routing-protocol-eigrp/22327-gre-flap.html