The Cisco perimeter router must be configured to have Link Layer Discovery Protocol (LLDP) disabled on all external interfaces.
Overview
| Finding ID | Version | Rule ID | IA Controls | Severity |
| V-216674 | CISC-RT-000360 | SV-216674r855821_rule | CCI-002403 | low |
| Description | ||||
| LLDP is a neighbor discovery protocol used to advertise device capabilities, configuration information, and device identity. LLDP is media-and-protocol-independent as it runs over layer 2; therefore, two network nodes that support different layer 3 protocols can still learn about each other. Allowing LLDP messages to reach external network nodes provides an attacker a method to obtain information of the network infrastructure that can be useful to plan an attack. | ||||
| STIG | Date | |||
| Cisco IOS XE Router RTR Security Technical Implementation Guide | 2025-05-16 | |||
Details
Check Text (C-216674r855821_chk)
This requirement is not applicable for the DODIN Backbone.
Step 1: Verify LLDP is not enabled globally via the command.
lldp run
By default LLDP is not enabled globally. If LLDP is enabled, proceed to step 2.
Step 2: Verify LLDP is not enabled on any external interface as shown in the example below:
interface GigabitEthernet0/1
ip address x.1.12.1 255.255.255.252
no lldp transmit
Note: LLDP is enabled by default on all interfaces once it is enabled globally; hence the command "lldp transmit" will not be visible on the interface configuration.
If LLDP transmit is enabled on any external interface, this is a finding.
Fix Text (F-17905r287974_fix)
Disable LLDP transmit on all external interfaces as shown in the example below:
R5(config)#int g0/1
R5(config-if)#no lldp transmit