Cisco Certified Network Associate (CCNA) Practice Exam

For auto-summarizing a network in EIGRP, what is the first command that should be executed?

1. (config)#router eigrp AS NUMBER

2. (config)#router rip

3. (config)#ip nat inside

4. (config)#interface fa0/0

The correct answer is: (config)#router eigrp AS NUMBER

The first command that should be executed for auto-summarizing a network in Enhanced Interior Gateway Routing Protocol (EIGRP) is the command that enters the EIGRP configuration mode, which is done by specifying the Autonomous System (AS) number. This command enables EIGRP on the router and allows the configuration of routing protocol parameters specific to EIGRP. By executing the command to enter EIGRP configuration mode, the router begins the process of participating in EIGRP and can then be configured for features such as auto-summarization, which allows for simpler route advertisement by summarizing routes at network boundaries. This is particularly useful in reducing routing table size and minimizing bandwidth usage on links. The other commands listed do not initiate EIGRP configuration settings directly. For example, entering RIP configuration mode or setting up NAT would not be relevant for configuring EIGRP auto-summarization. Similarly, accessing a specific interface would not set up the routing protocol necessary for EIGRP. Thus, entering the EIGRP configuration mode with the appropriate AS number is essential as the first step in effectively utilizing EIGRP's capabilities, including auto-summarization.