CompTIA Network+ (N10-007) — Question 30

A network administrator configures a router with the following IP address information:
Gigabit Ethernet 1 Interface: 10.10.0.1/24
Serial 0 Interface: 10.10.0.253/30
Clients are connected to a switch on the gigabit Ethernet interface; the ISP is connected to the Serial 0 interface. When the router configuration is complete and client devices are reconfigured, all clients report that they are unable to connect to the Internet. Which of the following is the MOST likely reason?

Answer options

• A. The router was configured with an incorrect IP address
• B. The router was configured with an incorrect default gateway
• C. The router was configured with an incorrect subnet mask
• D. The router was configured with an incorrect loopback address

Correct answer: C

Explanation

The correct answer is C because if the subnet mask is incorrect, it can prevent clients from communicating properly with the router or the ISP, leading to an inability to access the Internet. Options A and B could also cause connectivity issues, but the specifics of the configuration suggest that it's the subnet mask that is likely the primary problem. Option D is not relevant in this scenario as a loopback address is not utilized for client connectivity in this setup.