What DMVPN NHRP configuration ensures spokes form direct spoke-to-spoke tunnels when needed and otherwise use the hub?

The correct configuration enables DMVPN Phase 3, allowing spoke-to-spoke communication. On the hub, ip nhrp map multicast dynamic allows the hub to forward multicast traffic to spokes without static mappings, and ip nhrp redirect tells spokes that other spokes are available for direct tunnels. On the spokes, ip nhrp map multicast dynamic enables multicast forwarding, and ip nhrp shortcut allows spokes to bypass the hub and form direct tunnels with other spokes after learning their real IP addresses from the hub's redirect message. The tunnel mode gre multipoint command is essential on both hub and spokes for DMVPN. Incorrect options use nhs instead of map for dynamic multicast, which is not the standard command for this function, or they misconfigure shortcut and redirect commands, preventing proper spoke-to-spoke tunnel formation.