Cisco Certified Network Associate (CCNA) Practice Exam

What command is used to disable auto summary on an EIGRP router?

1. (config)#router eigrp AS NUMBER

2. (config)#no auto-summary

3. (config-router)#no summarize

4. (config)#disable auto-summary

The correct answer is: (config)#no auto-summary

The command used to disable auto summary on an EIGRP router is "no auto-summary". This command prevents EIGRP from summarizing routes at the classful boundary, allowing the router to send specific subnet information instead of a summarized route. Disabling auto summary is particularly important in scenarios where discontiguous networks exist, as it ensures that the routing information remains accurate and precise, ultimately improving network performance and functionality. Other options might not be appropriate for this context. For instance, entering the router EIGRP command simply puts you into the EIGRP configuration mode; it doesn’t disable summarization. The "no summarize" command does not exist in EIGRP configuration, and "disable auto-summary" is not a valid command syntax within the Cisco IOS. Therefore, "no auto-summary" is the correct command to disable auto summarization in EIGRP.