CCNA Practice Test 4 — 10 Questions

Question 1

A switch trunk is carrying several VLANs, but VLAN 99 traffic is failing. The trunk allowed list includes VLAN 99 on both sides. Which statement best explains why a VLAN can still fail even when it is allowed?

Choose an answer to begin — your selection is scored in the full session.

Accepted Answer

Because the VLAN may still be absent, inactive, or otherwise not operational locally even if it is allowed on the trunk. A VLAN can still fail across a trunk even when it is allowed because the allowed list is only one part of the overall design. In plain language, a switch may permit the VLAN on the link, but if the VLAN does not actually exist locally, is not active, or if some other trunk characteristic is inconsistent, traffic can still fail. This is an important CCNA troubleshooting principle: one correct line of configuration does not guarantee the full end-to-end condition is correct.

Candidates often stop at the allowed VLAN list because it is visible in common show commands. However, VLAN presence, local status, and other trunk parameters still matter. The best answer is the one recognizing that permission on the trunk does not automatically prove the entire VLAN path is healthy.

Answer

Because allowing a VLAN on a trunk automatically disables it

Answer

Because VLANs can cross trunks only when PAT is enabled

Answer

Because VLAN 99 must always be the native VLAN

Question 2

A route to 10.10.10.0/24 is learned through two OSPF paths. Both have the same prefix length and the same administrative distance, but one path has a lower OSPF metric. Which path is preferred?

Accepted Answer

The path with the lower OSPF metric. The path with the lower OSPF metric is preferred. In practical terms, when the prefix and route source are the same, the router uses the routing protocol’s internal path-selection logic. For OSPF, the lower metric is the more attractive path.

This is a clean example of metric-based selection within one routing protocol. Administrative distance is not the deciding factor here because the source protocol is the same on both paths.

Answer

The path with the higher OSPF metric

Answer

Both paths equally, because the administrative distance is the same

Answer

Neither path, because two OSPF routes to the same prefix are invalid

Question 3

An IPv6 host successfully reaches neighbors on its local segment, but it cannot reach remote IPv6 destinations. The host has a global unicast address and a correct prefix length. Which missing item is the strongest suspect?

Accepted Answer

A usable default router or next-hop route for off-link IPv6 traffic. The strongest suspect is the absence of a usable default router learned through IPv6 router advertisements or equivalent configuration. While local connectivity works because the host can communicate on its own link, remote IPv6 destinations require a next hop off the local segment. Option B is wrong because IPv6-to-IPv4 NAT is unnecessary for native IPv6 communication and would not be the primary cause of off-link failure. Option C is wrong because a VLAN trunk on the host NIC is for carrying multiple VLANs, not for enabling off-link routing. Option D is wrong because a second global unicast address does not provide a default route; it only adds another local address.

Answer

A NAT rule translating IPv6 to IPv4

Answer

A VLAN trunk on the host NIC

Answer

A second global unicast address on the same interface

Question 4

Which TWO commands can a network technician use on a modern Linux host to verify the IP address configuration and test reachability to a remote server?

Accepted Answer

ip addr. The `ip addr` command (option A) is the modern Linux utility for displaying IP address configuration, replacing the deprecated `ifconfig`. The `ping` command (option D) uses ICMP Echo Request/Reply messages to test Layer 3 reachability to a remote server. `ifconfig` (option B) is deprecated and not expected for current certification exams; `tracert` (option C) is a Windows command; `nslookup` (option E) performs DNS lookups but does not verify IP configuration or connectivity.

Answer

ifconfig

Answer

tracert

Answer

nslookup

Question 5

Which TWO interface errors are most likely caused by a mismatch in duplex settings between two connected switches?

Accepted Answer

Runts. A duplex mismatch occurs when one switch operates at full duplex while the other operates at half duplex. On the half-duplex side, frames arriving while the interface is transmitting are considered collisions, causing the frame to be truncated into fragments (runts). On the full-duplex side, the switch does not detect collisions but may receive incomplete frames, which are counted as runts if they are less than 64 bytes. CRC errors also spike because the truncated or corrupted frames fail the Frame Check Sequence (FCS) validation.

Answer

Giants

Answer

Input errors

Answer

Output errors

Answer

Flaps

Question 6

A wireless client joins the correct SSID and gets an address in the correct employee subnet, but cannot reach only one internal application while everything else works. Which troubleshooting area is the strongest first target?

Accepted Answer

The path or policy specific to that application, since general employee connectivity already works.. The strongest first target is the application path or policy specific to that application because the client already has general connectivity: it joined the correct SSID, authenticated, and obtained an IP address in the employee subnet. A failure limited to one internal application indicates that basic WLAN join, DHCP, and overall routing are working; therefore, ACLs, firewall rules, DNS resolution for that service, or application-specific policies are the likely cause. Option B (SSID broadcast setting) is irrelevant because the client successfully joined the SSID and has connectivity. Option C (voice VLAN on the wired access port) is not a first target because the symptom involves a single data application, not voice, and the client is on the employee subnet, not a voice VLAN. Option D (OSPF router ID on the client) is invalid because client devices do not typically run OSPF; OSPF runs on routers, not wireless clients.

Answer

The SSID broadcast setting, because the client must not be joined correctly.

Answer

The voice VLAN on the wired access port connected to the AP uplink.

Answer

The OSPF router ID on the client device.

Question 7

A router learns the same destination prefix from OSPF and from a static route configured with administrative distance 90. Which route is preferred by default?

Accepted Answer

The static route with distance 90. The static route is preferred because its administrative distance of 90 is lower than OSPF’s default administrative distance of 110. In practical terms, when the prefix length is the same, the router compares route-source trust next. The lower administrative distance wins.

This question is important because many learners remember that static routes are often strong choices but forget that administrative distance can be tuned. Here, that tuning explicitly makes the static route more preferred than OSPF.

Answer

The OSPF route, because dynamic routes always beat static routes

Answer

Both routes equally, because the prefix is identical

Answer

Neither route, because duplicate information is dropped

Question 8

A small office uses PAT for user Internet access. What mechanism does PAT use to allow many users to share one public address while keeping their sessions distinct?

Accepted Answer

Use transport-layer port values to distinguish multiple inside sessions behind one outside address.. PAT (Port Address Translation) distinguishes multiple inside sessions by rewriting the source port number for each connection while using the same public IP address. This transport-layer port translation allows many internal hosts to share one outside address without conflict. The correct answer identifies the use of port numbers, which is the core mechanism. Increasing the NAT pool or using static NAT would not enable sharing of a single public address. Changing private IPs to be identical or disabling routes are irrelevant to PAT's operation.

Answer

Convert all inside hosts to the same private IP address.

Answer

Increase the size of the NAT pool to include multiple public addresses.

Answer

Configure static NAT mappings for each inside host.

Question 9

Based on the exhibit, why is traffic to 192.168.40.200 using the default route instead of the intended static route?

Accepted Answer

The static route next hop is unreachable or invalid for forwarding.. The intended static route is not being used because the next hop for that static route is not reachable from the current routing table. In practical terms, a route can be configured, but the router still needs a way to resolve and forward to the next-hop address. If that next hop is unreachable, the route may not be installed or usable, so traffic falls back to the default route instead.

This is a realistic troubleshooting pattern because the configuration line alone can look correct until you compare it with actual reachability.

Answer

Default routes always override static routes.

Answer

The destination must be configured as a /16, not a /24.

Answer

Static routes can be used only if OSPF is disabled.

Question 10

A host is configured as 192.168.50.130/25. Which address is the broadcast address for its subnet?

Accepted Answer

192.168.50.255. A /25 divides the /24 into two blocks: 0–127 and 128–255. In plain language, because the host ends in 130, it belongs to the upper half, which starts at 128 and ends at 255. The last address in that block is the broadcast address, so the broadcast is 192.168.50.255.

This is a classic subnetting pattern because it tests whether you can identify not just the subnet, but also the reserved last address in that subnet.

Answer

192.168.50.127

Answer

192.168.50.128

Answer

192.168.50.254