IC3 Networking and Internet Fundamentals 6

Question 1

Several laptops in an office reach the internet without problems. One laptop shows an IPv4 address of 169.254.23.7 and can't open any websites, even though its Wi-Fi icon shows it is connected. What is the most likely cause?

Accepted Answer

The laptop couldn't get an address from a DHCP server, so it assigned itself one

Answer

Addresses in the 169.254.x.x range are APIPA (link-local) addresses. A device gives itself one of these automatically when it asks for an address from a DHCP server and gets no answer. Without a valid address, default gateway and DNS settings from DHCP, the laptop can't route traffic to the internet. A DNS problem would still leave the laptop with a normal address. A static IP conflict would show the configured address, not a 169.254 address.

Question 2

A user can successfully ping 8.8.8.8 by its IP address, but every website they type by name (for example, www.example.com) fails to load in every browser. Which component is most likely failing?

Accepted Answer

Name resolution (DNS)

Answer

A successful ping to a public IP address shows that the adapter, local network, default gateway and internet route all work. The only thing missing is turning names into IP addresses, which is DNS's job. A browser cache problem would not affect every browser at once.

Question 3

You connect to a coffee shop's open Wi-Fi and visit https://www.mybank.com/accounts/statements. Assuming HTTPS is working correctly and no VPN is used, what can the Wi-Fi operator most likely still see?

Accepted Answer

That your device connected to the domain www.mybank.com

Answer

HTTPS encrypts the page content, form data such as passwords, and the URL path. However, the domain name usually stays visible through DNS lookups and the server name your device sends when it opens the secure connection. The operator can tell which site you visited but not what you did there.

Question 4

A family has a smart TV, two phones and a laptop online at the same time. A 'What is my IP' website shows the same IP address on every device. Which router function explains this?

Accepted Answer

Network Address Translation (NAT), which maps many private addresses to one public address

Answer

Inside the home, each device has its own private IP address (such as 192.168.1.x). When traffic goes out to the internet, the router uses NAT to replace those private addresses with the household's single public IP and keeps track of which reply belongs to which device. DHCP gives each device a different private address, not the same one.

Question 5

A gamer upgrades their home internet from 100 Mbps to 1 Gbps, but online matches on a server on another continent still lag, with a ping of about 250 ms. What best explains why the upgrade didn't help?

Accepted Answer

The lag comes from latency caused by distance and routing, not from a lack of bandwidth

Answer

Bandwidth is how much data a connection can carry per second. Latency is how long each piece of data takes to make the round trip. Games send small amounts of data that need to arrive quickly, so a high ping from a distant server causes lag no matter how much bandwidth you have. Picking a closer server or a better route lowers latency. Buying a faster plan does not.

IC3 - Digital Literacy Certification Practice Test

IC3 - Digital Literacy Certification Practice Test

IC3 Networking and Internet Fundamentals 6