Understand why a device with IP 192.168.1.10 and DNS 8.8.8.8 cannot access the internet due to an incorrect subnet mask. Learn how subnet mask misconfiguration disrupts communication with the default gateway for the CompTIA A+ Core 1 220-1101 exam.
Table of Contents
Question
A technician is troubleshooting a network where a device with IP 192.168.1.10 cannot access the internet. The default gateway is 192.168.1.1, and DNS is set to 8.8.8.8. What is the most likely issue?
A. Incorrect subnet mask
B. Blocked outbound port 80
C. Misconfigured DNS server
D. Faulty NIC driver
E. Disabled DHCP
Answer
A. Incorrect subnet mask
Explanation
If the subnet mask is incorrect (e.g., 255.255.0.0 instead of 255.255.255.0), the device may not communicate properly with the default gateway, preventing internet access despite valid IP and DNS settings.
An incorrect subnet mask can prevent a device from properly communicating with its default gateway, even if the IP address and DNS server settings appear correct. For example, if the network uses a subnet mask of 255.255.255.0 but the device is configured with 255.255.0.0, the device will incorrectly interpret which addresses are local versus remote. This mismatch causes the device to fail in routing traffic to the gateway (192.168.1.1), resulting in no internet access. Proper subnet mask configuration ensures the device correctly identifies the network and gateway boundaries, enabling successful communication. Other issues like blocked ports, faulty drivers, or DHCP problems would typically manifest differently or affect broader connectivity aspects.
CompTIA A+ Core 1 220-1101 certification exam practice question and answer (Q&A) dump with detail explanation and reference available free, helpful to pass the CompTIA A+ Core 1 220-1101 exam and earn CompTIA A+ Core 1 220-1101 certification.