Traffic entering the tunnels is not restricted to only the authorized management packets based on destination address.
Similar to the OOBM model, when the production network is managed in-band, the management network could also be housed at a NOC that is located locally or remotely at a single or multiple interconnected sites. NOC interconnectivity as well as connectivity between the NOC and the managed networks’ premise routers would be enabled using either provisioned circuits or VPN technologies such as IPSec tunnels or MPLS VPN services.
Where IPSec technology is deployed to connect the managed network to the NOC, it is imperative that the traffic entering the tunnels is restricted to only the authorized management packets based on destination address.
For both the NOC and the managed network, the IPSec tunnel end points may be configured on the premise or gateway router, a VPN gateway firewall or VPN concentrator. Verify that all traffic from the managed network to the management network and vice-versa is secured via IPSec encapsulation.