RIPRouter Config

passive-interface [intf]

Prevents RIP updates from being sent out a specific interface while still allowing the interface to receive updates.

Syntax·Router Config

passive-interface [intf]

When to Use This Command

On a LAN interface where no other RIP routers exist, to reduce unnecessary broadcast traffic.
On a loopback interface to avoid advertising the loopback network via RIP.
On an interface connected to a stub network to prevent routing updates from being sent to hosts.
On an interface where you want to receive RIP updates but not participate in sending them.

Command Examples

Make GigabitEthernet0/1 passive for RIP

passive-interface GigabitEthernet0/1

router rip
 version 2
 network 192.168.1.0
 passive-interface GigabitEthernet0/1
 no auto-summary

The command is entered in router config mode. The output shows the running configuration for RIP, including the passive-interface statement. This means RIP updates will not be sent out GigabitEthernet0/1, but the router will still listen for RIP updates on that interface.

Make all interfaces passive and then enable specific ones

passive-interface default
no passive-interface Serial0/0/0

router rip
 version 2
 network 10.0.0.0
 passive-interface default
 no passive-interface Serial0/0/0
 no auto-summary

The 'passive-interface default' command sets all interfaces as passive. Then 'no passive-interface Serial0/0/0' re-enables sending RIP updates only on Serial0/0/0. This is useful when you want to send updates only on WAN links.

Understanding the Output

The output is typically part of the running configuration. Look for 'passive-interface' lines under the router rip configuration. Each line specifies an interface that will not send RIP updates. The 'passive-interface default' command makes all interfaces passive, and subsequent 'no passive-interface' commands override that for specific interfaces. In 'show ip protocols' output, you can see a list of passive interfaces under 'Passive Interface(s):'. If an interface is passive, it will not appear in the list of interfaces sending updates. A good configuration ensures that only necessary interfaces send updates to prevent unnecessary traffic and potential routing loops.

CCNA Exam Tips

Remember that passive-interface only stops sending updates, not receiving them.

In RIP, passive-interface is commonly used on LAN segments to reduce broadcast traffic.

The 'passive-interface default' command is a CCNA exam favorite for simplifying configuration.

Be aware that passive-interface does not affect the interface's ability to advertise its own network; it only stops sending RIP updates.

Common Mistakes

Assuming passive-interface stops both sending and receiving updates — it only stops sending.

Forgetting to apply 'no passive-interface' on WAN links after using 'passive-interface default'.

Applying passive-interface to a loopback interface unnecessarily, though it is harmless.

Related Commands

show ip protocols

Displays the current state of all IP routing protocols running on the router, including timers, filters, and network advertisements.

show running-config

Displays the current active configuration in DRAM, showing all non-default settings.

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