This requirement is not applicable for the DODIN Backbone. Review the router configuration to verify that filters are configured to allow or deny traffic for specific source and destination addresses as well as ports and protocols. In the example below, the router is peering BGP with DISN. ICMP echo and echo-reply packets are allowed for troubleshooting connectivity. WWW traffic is permitted inbound to the NIPRnet host-facing web server (x.12.1.22). Step 1: Verify that external interface has an inbound filter configured as shown in the example below: interfaces { ge-0/0/0 { unit 0 { family inet { filter { input FILTER_INBOUND_TRAFFIC; } address x.1.12.2/30; } } } Step 2: Verify that the inbound filter allows only traffic that is to be permitted into the network as shown in the example below: firewall { family inet { filter FILTER_INBOUND_TRAFFIC { term TCP_ESTABLISHED { from { tcp-established; } then accept; } term ALLOW_BGP { from { source-address { x.1.12.1/32; } protocol tcp; destination-port bgp; } then accept; } term ALLOW_PING { from { protocol icmp; icmp-type [ echo-reply echo-request ]; } then accept; } term ALLOW_WWW { from { destination-address { x.12.1.22/32; } protocol tcp; destination-port http; } then accept; } term DENY_ALL_OTHER { then { syslog; reject; } } } } } If the router is not configured to enforce approved authorizations for controlling the flow of information within the network based on organization-defined information flow control policies, this is a finding.