N10-009 Practice Test 31 — 15 Questions

Question 1

A user reports that they can access a web server by its IP address (e.g., 10.10.10.50) but cannot access it by its domain name (e.g., server.example.com). The technician verifies that the DNS server is reachable and that the name resolves correctly from other workstations on the same subnet. Which of the following should the technician check NEXT?

Accepted Answer

Check the DNS cache on the user's workstation. The user's workstation can reach the web server by IP but not by domain name, while other workstations resolve the name correctly. This strongly suggests a local DNS resolution issue specific to that workstation, such as a corrupted or stale DNS cache. Flushing the DNS cache with `ipconfig /flushdns` is the logical next step before investigating broader network or firewall issues.

Answer

Verify the default gateway configuration

Answer

Renew the DHCP lease

Answer

Disable the Windows Firewall

Question 2

A technician is troubleshooting an issue where a wireless client can associate with an access point but cannot obtain an IP address via DHCP. The technician checks the DHCP server and sees no lease requests from the client's MAC address. Which of the following is the most likely cause?

Accepted Answer

The AP is not configured with a DHCP relay. The client can associate with the AP but cannot obtain an IP address, and the DHCP server shows no lease requests from the client's MAC. This indicates that DHCP discovery broadcasts are not reaching the DHCP server, which is common when the client and server are on different subnets and the AP (or a Layer 3 device) is not configured with a DHCP relay (ip helper-address). Without a relay, broadcast DHCP messages are dropped at the router, so the server never sees the request.

Answer

The client's wireless adapter is faulty

Answer

The client's SSID is incorrect

Answer

The AP's radio is operating on the wrong channel

Question 3

A technician needs to connect two different networks and forward traffic based on IP addresses. Which of the following devices operates at Layer 3 of the OSI model and should be used?

Accepted Answer

Router. A router operates at Layer 3 (Network layer) of the OSI model and makes forwarding decisions based on IP addresses. It uses routing tables and protocols such as OSPF or BGP to determine the best path for packets between different networks. This makes it the correct device for connecting two distinct networks and forwarding traffic by IP address.

Answer

Hub

Answer

Switch

Answer

Bridge

Question 4

A user reports intermittent connectivity on a laptop that moves between floors. The signal strength fluctuates. Which tool would best help identify signal interference and dead zones?

Accepted Answer

Spectrum analyzer. A spectrum analyzer is the correct tool because it visualizes radio frequency (RF) energy across the 2.4 GHz and 5 GHz bands, allowing you to identify sources of interference (e.g., cordless phones, microwave ovens) and locate dead zones where signal strength drops below usable thresholds. Unlike other tools, it directly measures the RF environment rather than relying on logical-layer data.

Answer

Cable tester

Answer

Multimeter

Answer

Protocol analyzer

Question 5

A user reports they can access internal servers and the default gateway but cannot reach external websites. The technician checks the router's ACL and finds a rule that permits all outbound traffic. What is the most likely cause?

Accepted Answer

NAT configuration issue. The user can access internal servers and the default gateway, indicating Layer 3 connectivity within the local network. However, external websites are unreachable. Since the ACL permits all outbound traffic, the issue is not a blocked outbound rule. The most likely cause is a NAT configuration issue, such as missing or incorrect IP masquerading (PAT) on the router's outside interface, which prevents internal private IP addresses from being translated to a public IP address for internet access.

Answer

DNS resolution failure

Answer

Incorrect default gateway

Answer

Proxy server misconfiguration

Question 6

A user reports that they cannot access the company's internal web application at https://apps.internal.company.com. The technician can ping the server's IP address (10.10.10.20) successfully and also successfully telnet to 10.10.10.20 on port 443. However, the web browser displays 'Unable to connect'. What is the most likely cause?

Accepted Answer

The browser is configured to use an incorrect proxy server. The technician can ping the server IP and telnet to port 443, proving the server is reachable and the HTTPS service is listening. However, the browser fails to load the page, which points to a client-side issue. An incorrect proxy server configuration in the browser would cause the browser to send requests to a proxy that cannot reach the internal server, resulting in 'Unable to connect' despite successful network-level connectivity tests.

Answer

The web server service is stopped

Answer

DNS resolution is failing for the FQDN

Answer

A firewall is blocking TCP port 443

Question 7

A user reports that they cannot access the internet. The technician is able to ping the default gateway successfully but unable to ping a public IP address (e.g., 8.8.8.8). Which of the following is the most likely cause?

Accepted Answer

The router's default route is missing or misconfigured. Successful ping to the default gateway confirms Layer 2 and Layer 3 connectivity within the local subnet, but failure to ping a public IP like 8.8.8.8 indicates that traffic cannot leave the local network. This is most commonly caused by a missing or misconfigured default route on the router, which prevents the router from forwarding packets destined for external networks to the next-hop ISP gateway.

Answer

Incorrect DNS server configuration

Answer

Duplicate IP address on the network

Answer

Faulty network interface card

Question 8

A user reports that they cannot access an internal web server at http://intranet.company.local but can access other internet websites. The technician runs ping intranet.company.local and receives replies successfully. Which tool should the technician use next to isolate the issue?

Accepted Answer

nslookup. The technician can reach the server by IP (ping succeeds) but not by hostname (http://intranet.company.local), which points to a name resolution failure. nslookup is the correct next step because it queries DNS to verify whether the hostname resolves to the correct IP address, isolating the issue to DNS rather than connectivity or server availability.

Answer

tracert

Answer

netstat

Answer

ipconfig

Question 9

A user reports that they cannot access a web server by its URL but can access it by IP address. A technician checks the DNS server and finds it is reachable. What is the most likely cause?

Accepted Answer

DNS resolution failure for that specific record. The user can access the web server by IP address but not by URL, which indicates that the name-to-IP resolution is failing. Since the DNS server is reachable, the issue is not with network connectivity to the DNS server but rather with the specific DNS record for that web server. This is a classic DNS resolution failure for that specific record, often due to a missing or incorrect A or AAAA record.

Answer

Incorrect default gateway

Answer

Firewall blocking port 80

Answer

IP conflict on the user's workstation

Question 10

A user reports that they can connect to the internet by IP address but cannot access any websites by domain name. Which command-line tool should a technician use first to isolate the issue?

Accepted Answer

nslookup. The user can reach the internet by IP address but not by domain name, which indicates a DNS resolution failure. The `nslookup` command queries DNS servers directly to test name resolution, making it the correct first step to isolate whether the issue is with the DNS server, the client's DNS configuration, or a network path to the DNS server.

Answer

ping

Answer

tracert

Answer

netstat

Question 11

A user reports that they can connect to the corporate Wi-Fi network but cannot access any network resources including the intranet and internet. The IP configuration shows an IP address of 169.254.25.100 with a subnet mask of 255.255.0.0. What is the most likely cause?

Accepted Answer

The DHCP server is unavailable or the request is not reaching it. The IP address 169.254.25.100 with a subnet mask of 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, which is assigned by the operating system when a DHCP server is unavailable or the DHCP request fails. Since the user can connect to Wi-Fi but cannot access any network resources, the most likely cause is that the DHCP server is not responding or the DHCP discover/offer/request/ack sequence is failing, leaving the device with a link-local address that cannot route to the corporate network or internet.

Answer

The DNS server is not responding

Answer

The subnet mask is incorrect

Answer

The switch port has port security enabled that has blocked the device

Question 12

A user reports that they cannot access any network resources. The technician runs 'ipconfig' on the workstation and sees that the IP address is 169.254.23.45 with a subnet mask of 255.255.0.0. What is the most likely cause of this issue?

Accepted Answer

The DHCP server is unreachable or not functioning.. The IP address 169.254.23.45 with a subnet mask of 255.255.0.0 is an Automatic Private IP Addressing (APIPA) address, which is assigned by the operating system when a DHCP discovery attempt fails. This indicates that the workstation was unable to contact a DHCP server to obtain a valid IP configuration, making an unreachable or non-functioning DHCP server the most likely cause.

Answer

The workstation's network cable is unplugged.

Answer

The DNS server is not responding.

Answer

The workstation has been assigned a static IP address in the wrong subnet.

Question 13

A user reports that they cannot access any network resources. The technician checks the IP configuration and sees that the workstation has an IP address of 169.254.1.5. What is the most likely cause?

Accepted Answer

The DHCP server is unavailable. The IP address 169.254.1.5 is an Automatic Private IP Addressing (APIPA) address (169.254.0.0/16 range), which Windows assigns when a DHCP client fails to receive a lease from a DHCP server. Since the workstation cannot obtain a valid IP configuration, it cannot communicate with any network resources, confirming that the DHCP server is unavailable.

Answer

The DNS server is down

Answer

The default gateway is incorrect

Answer

The subnet mask is mismatched

Question 14

A user's computer obtains an IP address from DHCP, can ping the default gateway, but cannot access any external websites. The technician runs 'tracert 8.8.8.8' from the user's computer. The first hop shows the default gateway with low latency, but the second hop shows a timeout. What is the most likely cause?

Accepted Answer

The router's default route pointing to the ISP is missing or incorrectly configured.. The traceroute shows that the user's computer can reach the default gateway (first hop) but times out at the second hop, which is the ISP's router. This indicates that the local router does not have a valid default route pointing to the ISP, so it cannot forward traffic beyond the local subnet. Without a correct default route, packets destined for external networks (like 8.8.8.8) are dropped, even though the user's computer can ping the gateway and obtain an IP via DHCP.

Answer

The user's computer firewall is blocking outbound web traffic.

Answer

The DNS server is not resolving domain names.

Answer

The ISP's DNS server is unreachable.

Question 15

A workstation with IP address 10.0.1.5/24 needs to communicate with a server at 10.0.2.10/24. The workstation's default gateway is configured as 10.0.1.1. Which of the following will the workstation do with the IP packets destined for the server?

Accepted Answer

Send the packets to the default gateway.. The workstation's IP address (10.0.1.5/24) and the server's IP address (10.0.2.10/24) are on different subnets (10.0.1.0/24 vs. 10.0.2.0/24). When a host determines that the destination is not on the same local network, it will not attempt direct delivery via ARP. Instead, it forwards the IP packet to its configured default gateway (10.0.1.1), which then routes the packet toward the server's subnet.

Answer

Send the packets directly to the server using ARP.

Answer

Send the packets to the DNS server for resolution.

Answer

Drop the packets because the server is on a different network.