The perimeter router must be configured to not be a Border Gateway Protocol (BGP) peer to an alternate gateway service provider.
Overview
Finding ID
Version
Rule ID
IA Controls
Severity
V-207114
SRG-NET-000019-RTR-000009
SV-207114r604135_rule
High
Description
ISPs use BGP to share route information with other autonomous systems (i.e. other ISPs and corporate networks). If the perimeter router was configured to BGP peer with an ISP, NIPRnet routes could be advertised to the ISP; thereby creating a backdoor connection from the Internet to the NIPRnet.