Information
Information flow control regulates authorized information to travel within a network and between interconnected networks. Controlling the flow of network traffic is critical so it does not introduce any unacceptable risk to the network infrastructure or data. An example of a flow control restriction is blocking outside traffic claiming to be from within the organization. For most routers, internal information flow control is a product of system design.
NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.
Solution
This requirement is not applicable for the DODIN Backbone.
Step 1: Configure an ACL to allow or deny traffic as shown in the example below.
R1(config)#ip access-list extended FILTER_PERIMETER
R1(config-ext-nacl)#permit tcp any any established
R1(config-ext-nacl)#permit tcp host x.12.1.9 host x.12.1.10 eq bgp
R1(config-ext-nacl)#permit tcp host x.12.1.9 eq bgp host x.12.1.10
R1(config-ext-nacl)#permit icmp host x.12.1.9 host x.12.1.10 echo
R1(config-ext-nacl)#permit icmp host x.12.1.9 host x.12.1.10 echo-reply
R1(config-ext-nacl)#permit tcp any host x.12.1.22 eq www
R1(config-ext-nacl)#deny ip any any log-input
R1(config-ext-nacl)#exit
Step 2: Apply the ACL inbound on all external interfaces.
R2(config)#int g0/0
R1(config-if)#ip access-group FILTER_PERIMETER in