The NSX Tier-0 Gateway router must be configured to use its loopback address as the source address for Internal Border Gateway Protocol (IBGP) peering sessions.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
low	V-265468	SRG-NET-000512-RTR-000001	NT0R-4X-000091	SV-265468r994754_rule	2024-12-13	1

Description
Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of the Border Gateway Protocol (BGP) routers. It is easier to construct appropriate ingress filters for router management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the router’s loopback address instead of the numerous physical interface addresses. The routers within the iBGP domain should also use loopback addresses as the source address when establishing BGP sessions.

Description

Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of the Border Gateway Protocol (BGP) routers. It is easier to construct appropriate ingress filters for router management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the router’s loopback address instead of the numerous physical interface addresses. The routers within the iBGP domain should also use loopback addresses as the source address when establishing BGP sessions.

ℹ️ Check
If the Tier-0 Gateway is not using iBGP, this is Not Applicable. From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways. For every Tier-0 Gateway with BGP enabled, expand the Tier-0 Gateway. Expand BGP, click on the number next to BGP Neighbors, then view the source address for each neighbor. If the Source Address is not configured as the Tier-0 Gateway loopback address for the iBGP session, this is a finding.

ℹ️ Check

If the Tier-0 Gateway is not using iBGP, this is Not Applicable. From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways. For every Tier-0 Gateway with BGP enabled, expand the Tier-0 Gateway. Expand BGP, click on the number next to BGP Neighbors, then view the source address for each neighbor. If the Source Address is not configured as the Tier-0 Gateway loopback address for the iBGP session, this is a finding.

✔️ Fix
To configure a loopback interface, do the following: From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways and expand the target Tier-0 gateway. Expand interfaces and click "Add Interface". Enter a name, select "Loopback" as the Type, enter an IP address, select an Edge Node for the interface, then click "Save". Note: More than one loopback may need to be configured depending on the routing architecture. To set the source address for BGP neighbors, do the following: From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways >> expand the target Tier-0 gateway. Expand BGP >> next to BGP Neighbors, click on the number present to open the dialog >> select "Edit" on the target BGP Neighbor. Under Source Addresses, configure the source address with the loopback address and click "Save".

✔️ Fix

To configure a loopback interface, do the following: From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways and expand the target Tier-0 gateway. Expand interfaces and click "Add Interface". Enter a name, select "Loopback" as the Type, enter an IP address, select an Edge Node for the interface, then click "Save". Note: More than one loopback may need to be configured depending on the routing architecture. To set the source address for BGP neighbors, do the following: From the NSX Manager web interface, go to Networking >> Connectivity >> Tier-0 Gateways >> expand the target Tier-0 gateway. Expand BGP >> next to BGP Neighbors, click on the number present to open the dialog >> select "Edit" on the target BGP Neighbor. Under Source Addresses, configure the source address with the loopback address and click "Save".