This scenario tests repeated authentication according to RFC 4478.
The initiator carol sets a short reauth_time=20s but the responder
moon defining a much larger reauth_time=60m proposes this
value via an AUTH_LIFETIME notification to the initiator. The initiator
ignores this notification and schedules the IKE reauthentication at its
configured time. A ping from carol to client alice
hiding in the subnet behind moon tests if the CHILD_SA has been
recreated under the new IKE_SA.