The perimeter router must be configured to deny network traffic by default and allow network traffic by exception.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-78237	SRG-NET-000202-RTR-000001	SV-92943r1_rule		High

Description
A deny-all, permit-by-exception network communications traffic policy ensures that only connections that are essential and approved are allowed. This requirement applies to both inbound and outbound network communications traffic. All inbound and outbound traffic must be denied by default. Firewalls and perimeter routers should only allow traffic through that is explicitly permitted. The initial defense for the internal network is to block any traffic at the perimeter that is attempting to make a connection to a host residing on the internal network. In addition, allowing unknown or undesirable outbound traffic by the firewall or router will establish a state that will permit the return of this undesirable traffic inbound.

Description

A deny-all, permit-by-exception network communications traffic policy ensures that only connections that are essential and approved are allowed. This requirement applies to both inbound and outbound network communications traffic. All inbound and outbound traffic must be denied by default. Firewalls and perimeter routers should only allow traffic through that is explicitly permitted. The initial defense for the internal network is to block any traffic at the perimeter that is attempting to make a connection to a host residing on the internal network. In addition, allowing unknown or undesirable outbound traffic by the firewall or router will establish a state that will permit the return of this undesirable traffic inbound.

STIG	Date
Router Security Requirements Guide	2020-06-30

Details

Check Text ( C-77793r1_chk )
This requirement is not applicable for the DoDIN Backbone. Review the router configuration to verify that the access control list (ACL) or filter is configured to allow specific ports and protocols and deny all other traffic. The filter must be configured inbound on all external interfaces. If the ACL or filter is not configured to allow specific ports and protocols and deny all other traffic, this is a finding. If the filter is not configured inbound on all external interfaces, this is a finding.

Check Text ( C-77793r1_chk )

This requirement is not applicable for the DoDIN Backbone.

Review the router configuration to verify that the access control list (ACL) or filter is configured to allow specific ports and protocols and deny all other traffic.

The filter must be configured inbound on all external interfaces.

If the ACL or filter is not configured to allow specific ports and protocols and deny all other traffic, this is a finding.

If the filter is not configured inbound on all external interfaces, this is a finding.

Fix Text (F-84965r1_fix)
This requirement is not applicable for the DoDIN Backbone. Configure the perimeter router to deny network traffic by default and allow network traffic by exception.