The NSX Tier-0 Gateway router must be configured to use encryption for Open Shortest Path First (OSPF) routing protocol authentication.

A rogue router could send a fictitious routing update to convince a site's perimeter router to send traffic to an incorrect or even a rogue destination. This diverted traffic could be analyzed to learn confidential information about the site's network or used to disrupt the network's ability to communicate with other networks. This is known as a "traffic attraction attack" and is prevented by configuring neighbor router authentication for routing updates. However, using clear-text authentication provides little benefit since an attacker can intercept traffic and view the authentication key. This would allow the attacker to use the authentication key in an attack.

This requirement applies to all IPv4 and IPv6 protocols that are used to exchange routing or packet forwarding information; this includes all Interior Gateway Protocols (such as OSPF, Enhanced Interior Gateway Routing Protocol [EIGRP], and Intermediate System to Intermediate System [IS-IS]) and exterior gateway protocols (such as Border Gateway Protocol [BGP]), multiprotocol label switching (MPLS)-related protocols (such as Label Distribution Protocol [LDP]), and multicast-related protocols.

Typically routing protocols must be setup on both sides so knowing the authentication key does not necessarily mean an attacker would be able to setup a rogue router and peer with a legitimate one and inject malicious routes.