The Multicast Source Discovery Protocol (MSDP) Cisco ACI must be configured to use its loopback address as the source address when originating MSDP traffic.

Severity	Group ID	Group Title	Version	Rule ID	Date	STIG Version
low	V-272099	SRG-NET-000512-RTR-000011	CACI-RT-000039	SV-272099r1114110_rule	2025-06-18	1

Description
Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of MSDP 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.

Description

Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of MSDP 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.

ℹ️ Check
Verify that the loopback interface is used as the source address for all MSDP packets generated by the router. 1. Navigate to Fabric >> Fabric Policies >> Policies >> Pod >> Management Access on the APIC GUI to find the relevant settings. 2. Verify the loopback interface IP address is used as the source address. If the router does not use its loopback address as the source address when originating MSDP traffic, this is a finding.

ℹ️ Check

Verify that the loopback interface is used as the source address for all MSDP packets generated by the router. 1. Navigate to Fabric >> Fabric Policies >> Policies >> Pod >> Management Access on the APIC GUI to find the relevant settings. 2. Verify the loopback interface IP address is used as the source address. If the router does not use its loopback address as the source address when originating MSDP traffic, this is a finding.

✔️ Fix
Configure the router to use its loopback address is used as the source address when sending MSDP packets. 1. Navigate to Fabric >> Fabric Policies >> Policies >> Pod >> Management Access to find the relevant settings. 2. Specify the loopback interface IP address as the source address.