V-256044

Discussion

For in-band management, the management network must have its own subnet in order to enforce control and access boundaries provided by Layer 3 network nodes, such as routers and firewalls. Management traffic between the managed network elements and the management network is routed via the same links and nodes as that used for production or operational traffic. Safeguards must be implemented to ensure that the management traffic does not leak past the perimeter of the managed network.

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This requirement is not applicable for the DODIN backbone.

The Arista perimeter router of the managed network must be configured with an access control list (ACL) or filter on the egress interface to block all management traffic.

Step 1: To verify the configuration is blocking all outbound traffic destined to management network, execute the command "sh ip access-list".

ip access-list FILTER_MANAGEMENT_SUBNET
  deny ip any 172.20.1.0 0.0.0.255 log
  permit ip any any

Step 2: To verify the filter is applied on egress interface, execute the command "sh run int ethernet YY".

interface ethernet 3
ip access-group FILTER_MANAGEMENT_SUBNET out

If management traffic is not blocked at the perimeter, this is a finding.