Question 1easymultiple choice
Full question →easymultiple choiceObjective-mapped
A user reports that they cannot access any company resources. The technician runs 'ipconfig' and sees that the workstation has an IP address of 169.254.100.25 with a subnet mask of 255.255.0.0. The technician also notices that the 'Default Gateway' is blank. What is the most likely cause?
Answer choices
Why each option matters
Good practice is not just finding the correct option. The wrong answers often show the exact trap the exam wants you to fall into.
A
Distractor review
The DNS server is not responding.
DNS failure would cause name resolution issues, but the workstation would still get a proper DHCP IP. APIPA addresses appear only when DHCP fails.
B
Best answer
The DHCP server is unavailable or unreachable.
APIPA is assigned when a DHCP client cannot contact a DHCP server; this is the most likely cause.
C
Distractor review
The workstation has a static IP address configured.
A static IP would not result in 169.254.x.x; APIPA is only used when DHCP fails and no static IP is set.
D
Distractor review
The network cable is unplugged.
If the cable were unplugged, the NIC would not have a link and likely show a disconnected status, not an APIPA address. APIPA requires a link to be active.
Common exam trap
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Technical deep dive
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
- CIDR notation defines the prefix length.
- Block size helps identify subnet boundaries.
- Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
- The required host count determines the smallest suitable subnet.
TExam Day Tips
- Write the block size before choosing the subnet.
- Check whether the question asks for hosts, subnets or a specific address range.
- Do not confuse /24, /25, /26 and /27 host counts.
Related practice questions
Related N10-009 practice-question pages
Use these pages to review the topic behind this question. This is how one missed question becomes focused revision.
Network+ network fundamentals practice questions
Practise N10-009 questions linked to Network+ network fundamentals.
Network+ implementation practice questions
Practise N10-009 questions linked to Network+ implementation.
Network+ operations practice questions
Practise N10-009 questions linked to Network+ operations.
Network+ security practice questions
Practise N10-009 questions linked to Network+ security.
Network+ troubleshooting practice questions
Practise N10-009 questions linked to Network+ troubleshooting.
More questions from this exam
Keep practising from the same exam bank, or move into a focused topic page if this question exposed a weak area.
Question 1
A network engineer needs to connect two switches located 400 meters apart. The cable run includes high electromagnetic interference from nearby machinery. The engineer decides to use fiber optic cabling. Which transceiver type and fiber combination should be used to ensure the link reaches 400 meters while remaining cost-effective?
Question 2
A network engineer is designing a new switched network and needs to ensure that broadcast traffic from one department does not reach another department's workstations. The engineer plans to use VLANs. Which of the following must be configured on the switches to isolate broadcast domains as intended?
Question 3
A security engineer is configuring a site-to-site VPN between two branch offices. The requirement is to encrypt all traffic between the two networks using IPsec. Which IPsec mode should be used to encrypt the entire IP packet including the original header?
Question 4
A network administrator is connecting two switches to increase bandwidth and provide redundancy. Which technology should be used to combine multiple physical links into a single logical link?
Question 5
A network administrator is experiencing issues where unauthorized devices are offering IP addresses to clients, causing connectivity problems. Which security feature should be enabled on switches to prevent this?
Question 6
A network administrator is troubleshooting a connectivity issue and suspects the problem is related to the physical cabling. At which layer of the OSI model should the administrator begin their investigation?
FAQ
Questions learners often ask
What does this N10-009 question test?
CIDR notation defines the prefix length.
What is the correct answer to this question?
The correct answer is: The DHCP server is unavailable or unreachable. — An IP address starting with 169.254.x.x is an Automatic Private IP Addressing (APIPA) address, assigned when a DHCP client fails to obtain an IP from a DHCP server. The lack of a default gateway confirms the workstation was unable to reach any DHCP server, so it self-assigned a link-local address. This typically occurs when the DHCP server is unavailable or the client cannot communicate with it.
What should I do if I get this N10-009 question wrong?
Then try more questions from the same exam bank and focus on understanding why the wrong options are tempting.
Discussion
Loading comments…
Sign in to join the discussion.