Cisco Certified Support Technician (CCST) NetworkingIP ConnectivityMedium
A network technician is configuring EIGRP on a Cisco router and wants to ensure that a specific interface does not send or receive EIGRP routing updates, but networks connected to it are still advertised by EIGRP. Which EIGRP command should be used on that interface?
- Aip passive-interface default
- Bno passive-interface GigabitEthernet0/1
- Cpassive-interface GigabitEthernet0/1
- Dshutdown GigabitEthernet0/1
Show answer & explanationAnswer & explanation
Correct answer: C. passive-interface GigabitEthernet0/1
The 'passive-interface' command prevents routing updates from being sent or received on a specified interface, while still allowing the network connected to that interface to be advertised by EIGRP. This is commonly used on interfaces connected to end-user segments.
Why the other options are wrong
- A. This command makes all interfaces passive by default, requiring 'no passive-interface' on active ones.
- B. This command would make a previously passive interface active again, sending and receiving updates.
- D. The 'shutdown' command administratively disables the interface, preventing any traffic or routing updates.
EIGRP Passive Interface
A passive interface in EIGRP prevents routing updates from being sent out or received on that specific interface while still allowing the network connected to it to be advertised by EIGRP.
- Prevents unnecessary routing updates on LAN segments.
- Enhances security by not sending updates to untrusted networks.
- Configured using the 'passive-interface <interface-type/number>' command under the EIGRP router configuration.
Memory trick: EIGRP interfaces can be chatty or quiet, choose wisely for security.