Cisco IOS Cookbook, 2nd Edition

Disabling EIGRP on an Interface

Problem

You want to disable an interface from participating in EIGRP.

Solution

You can prevent an interface from participating in EIGRP by simply designating it as passive:

Router1#configure terminal 
Enter configuration commands, one per line.  End with CNTL/Z.
Router1(config)#router eigrp 55
Router1(config-router)#passive-interface Serial0/1
Router1(config-router)#exit
Router1(config)#end
Router1#

Discussion

The passive-interface command in EIGRP prevents directly connected routers from establishing an EIGRP neighbor relationship. Since they can’t become neighbors, they will never exchange routing information. This is critically different from the way RIP behaves, as we saw in Chapter 6. In RIP, making an interface passive means that it will still accept routes; it just won’t send them. But with EIGRP, a passive interface will not send or receive any routing information.

Furthermore, configuring one router to be passive means that it can’t form an EIGRP adjacency relationship with any other routers through this interface. So if there are only two routers on a link, you can disable EIGRP on that link by simply configuring one of the routers with a passive interface.

You can see the neighbor relationships with the following command:

Router1#show ip eigrp neighbors IP-EIGRP neighbors for process 55 H Address Interface Hold Uptime SRTT RTO Q Seq Type (sec) (ms) Cnt Num 0 172.25.2.2 Se0/0.2 11 00:07:03 1563 5000 0 81 3 172.25.1.7 Fa0/0.1 77 00:18:17 11 200 0 348 ...