Cisco Certified Network Associate (CCNA) Practice Exam 2025 - Free CCNA Practice Questions and Study Guide

The command to configure a passive interface in EIGRP is indeed "passive-interface INTERFACE NUMBER." When you mark an interface as passive in EIGRP, it prevents the transmission of EIGRP hello packets on that interface. This is particularly useful in scenarios where you do not want to form neighbor adjacencies on certain interfaces—commonly on interfaces connected to end hosts or when connecting to a service provider.

By designating an interface as passive, the EIGRP process will not send out hello packets on it; however, the interface is still allowed to receive EIGRP updates. This can enhance network security and reduce unnecessary traffic while still enabling routing information to be processed for that interface.

In contrast, the other options do not pertain directly to the configuration of a passive interface. Enabling EIGRP with the "router eigrp AS NUMBER" command allows the routing protocol to operate but does not configure passive interfaces by itself. The "no-auto-summary" command is used to control automatic summarization in EIGRP, which affects how routes are advertised but not the interface behavior directly. Lastly, "show eigrp neighbors" is a command intended for displaying the current EIGRP neighbor relationships but does not involve