V-221033

Discussion

Using a loopback address as the source address offers a multitude of uses for security, access, management, and scalability of backbone switches. It is easier to construct appropriate ingress filters for switch management plane traffic destined to the network management subnet since the source addresses will be from the range used for loopback interfaces instead of from a larger range of addresses used for physical interfaces. Log information recorded by authentication and syslog servers will record the switch's loopback address instead of the numerous physical interface addresses.

Check Content

Review the switch configuration to determine if it is compliant with this requirement.

Verify that a loopback address has been configured as shown in the example below:

interface Loopback0
 ip address 10.1.1.1 255.255.255.255

By default, switches will use its loopback address for LDP peering. If an address has not be configured on the loopback interface, it will use its physical interface connecting to the LDP peer. If the router-id command is specified that overrides this default behavior, verify that it is a loopback interface as shown in the example below:

mpls ldp router-id Loopback0

If the switch is not configured to use its loopback address for LDP peering, this is a finding.