Traffic from the managed network is able to access the OOBM gateway router
If the gateway router is not a dedicated device for the OOBM network, several safeguards must be implemented for containment of management and production traffic boundaries. It is imperative that hosts from the managed network are not able to access the OOBM gateway rouiter.
Ensure that traffic from the managed network is not able to access the OOBM gateway router using either receive path or interface ingress ACLs.
Review the ACL or filters for the router’s receive path and verify that only traffic sourced from the management network is allowed to access the router. This would include both management and control plane traffic.