CCNA Network Infrastructure and Connectivity Practice Question
Exhibit
MLS# show ip interface brief | include Vlan Vlan10 192.168.10.1 YES manual up up Vlan20 192.168.20.1 YES manual up up
Exhibit: A host on VLAN 10 can ping the local SVI but not a server in VLAN 20. The Layer 3 switch has both VLAN interfaces up. What is the next item to verify first?
⚠ Common exam trap
A frequent exam trap is to overlook the remote device’s default gateway configuration and instead suspect the Layer 3 switch’s routing or VLAN setup. Candidates often assume that because the VLAN interfaces are up, routing must be functional. However, if the server in VLAN 20 lacks the correct default gateway pointing to its VLAN SVI, it cannot return traffic to the source host, causing failed pings. This one-way communication failure can mislead candidates into troubleshooting switch settings unnecessarily, wasting time and missing the root cause.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Whether the server in VLAN 20 has the correct default gateway
If the source host can reach its own default gateway, the local VLAN and access port are probably fine. The next practical check is whether the server in VLAN 20 has the correct IP address, mask, and default gateway configured.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Whether the server in VLAN 20 has the correct default gateway
Why this is correct
The most likely fault is that the server in VLAN 20 lacks a properly configured default gateway (or has a gateway that points to a different router/switch). When the VLAN 10 host pings the server, the ICMP echo request is routed by the switch's SVI to VLAN 20, but if the server cannot send the echo reply back through the correct next hop, the ping fails. This creates a one-way reachability issue that is a classic symptom of an end-host gateway misconfiguration, not a problem with the switch's routing table or trunking.
- ✗
Whether the switch should disable IP routing
Why it's wrong here
Disabling IP routing on the switch would completely break the path between VLAN 10 and VLAN 20, because the switch's SVI would no longer forward packets between those subnets. The fact that the host can already ping its local SVI indicates that the switch's layer 3 interface is up and addressed correctly; the problem lies beyond the local subnet. To route between VLANs, IP routing must remain enabled—either on the switch (inter-VLAN routing) or on an external router—so disabling it is not a viable fix and would only worsen the situation.
When this WOULD be correct
If the question described a scenario where the switch is acting as a Layer 2 switch and inter-VLAN routing is not required (e.g., all hosts in the same subnet), then disabling IP routing would be correct to prevent unintended routing behavior.
- ✗
Whether VLAN 10 should be the native VLAN
Why it's wrong here
VLAN 10 being the native VLAN is irrelevant to this symptom. Native VLAN configuration only affects how frames are tagged on 802.1Q trunk links; frames on the native VLAN are sent untagged. The host's ability to ping its local SVI and then fail to reach a server in another VLAN points to layer 3 forwarding issues, not to the layer 2 trunk encapsulation or native VLAN mismatch. Checking native VLAN settings would be appropriate only if there were complete L2 connectivity failures, not selective inter-VLAN reachability.
When this WOULD be correct
This option would be correct if the question described a scenario where a host in VLAN 10 cannot communicate with a host in VLAN 20 across a trunk link, and the switch ports are configured with mismatched native VLANs, causing untagged frames to be dropped or misdelivered.
- ✗
Whether the host should use a /8 mask instead of /24
Why it's wrong here
Changing the host's subnet mask from /24 to /8 would make the host assume the entire 10.0.0.0/8 address space is directly connected on its own VLAN. It would then attempt to ARP for the server's IP address instead of sending the packet to its default gateway, breaking communication even more. The given symptom—host can ping the local SVI—shows the host is already using a proper /24 mask and routing locally through its gateway; a /8 mask would create a completely different ARP-based failure, not resolve the current one.
When this WOULD be correct
If the host could not ping the local SVI and the question described connectivity issues to any destination, verifying the subnet mask (e.g., /8 vs /24) would be appropriate to rule out misconfiguration.
Option-by-option analysis
Why each answer is right or wrong
Understanding why wrong answers are wrong — and when they would be correct — is what separates a 750 score from a 900. The 200-301 exam frequently reuses these exact scenarios with slightly different constraints.
✓Whether the server in VLAN 20 has the correct default gatewayCorrect answer▾
Why this is correct
The most likely fault is that the server in VLAN 20 lacks a properly configured default gateway (or has a gateway that points to a different router/switch). When the VLAN 10 host pings the server, the ICMP echo request is routed by the switch's SVI to VLAN 20, but if the server cannot send the echo reply back through the correct next hop, the ping fails. This creates a one-way reachability issue that is a classic symptom of an end-host gateway misconfiguration, not a problem with the switch's routing table or trunking.
✗Whether the switch should disable IP routingWrong answer — click to see why▾
Why this is wrong here
The host can ping the local SVI, indicating Layer 3 connectivity on VLAN 10. The issue is reaching VLAN 20, which is a routing problem, not a routing disablement. Disabling IP routing would break all inter-VLAN communication, not just this one.
★ When this WOULD be the correct answer
If the question described a scenario where the switch is acting as a Layer 2 switch and inter-VLAN routing is not required (e.g., all hosts in the same subnet), then disabling IP routing would be correct to prevent unintended routing behavior.
Why candidates choose this
Candidates may think that disabling IP routing is a quick fix for connectivity issues without understanding that the SVI ping success proves routing is working locally, and the real problem is likely a missing or incorrect default gateway on the server.
✗Whether VLAN 10 should be the native VLANWrong answer — click to see why▾
Why this is wrong here
The native VLAN configuration affects untagged traffic on trunk ports, not inter-VLAN routing. Since the host can ping the local SVI but not a server in VLAN 20, the issue is likely a missing or incorrect default gateway on the server, not the native VLAN.
★ When this WOULD be the correct answer
This option would be correct if the question described a scenario where a host in VLAN 10 cannot communicate with a host in VLAN 20 across a trunk link, and the switch ports are configured with mismatched native VLANs, causing untagged frames to be dropped or misdelivered.
Why candidates choose this
Candidates may confuse native VLAN configuration with inter-VLAN routing, thinking that setting the correct native VLAN is necessary for Layer 3 communication between VLANs, especially when trunk ports are involved.
✗Whether the host should use a /8 mask instead of /24Wrong answer — click to see why▾
Why this is wrong here
The host can ping the local SVI, indicating its IP configuration (including subnet mask) is correct for VLAN 10. The issue is inter-VLAN routing, not the host's subnet mask.
★ When this WOULD be the correct answer
If the host could not ping the local SVI and the question described connectivity issues to any destination, verifying the subnet mask (e.g., /8 vs /24) would be appropriate to rule out misconfiguration.
Why candidates choose this
Candidates may confuse a host's inability to reach a remote subnet with a subnet mask mismatch, assuming the mask is too restrictive for routing.
Analysis generated from the official 200-301blueprint and verified against question context. The “when correct” sections are what AI assistants cite when candidates ask “what’s the difference between these options?”
Visual reference
Quick reference
IPv4 Address Class Summary
| Class | First Octet Range | Default Mask | Networks | Hosts per Network |
|---|---|---|---|---|
| A | 1–126 | /8 (255.0.0.0) | 126 | 16,777,214 |
| B | 128–191 | /16 (255.255.0.0) | 16,384 | 65,534 |
| C | 192–223 | /24 (255.255.255.0) | 2,097,152 | 254 |
| D | 224–239 | N/A | Multicast groups | — |
| E | 240–255 | N/A | Reserved / experimental | — |
127.x.x.x is reserved for loopback. Modern networks use CIDR (classless) rather than classful addressing.
Go deeper
Related to this question
Learn chapter
IPv4 Addressing and Address Classes
Key term
Ping
Ping is a network utility used to test whether a remote computer or device is reachable across an IP network and to measure the round-trip time of data packets.
Key term
ICMP
ICMP is a network-layer protocol used by network devices to send error messages and operational information about network connectivity.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This 200-301 practice question is part of Courseiva's free Cisco certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the 200-301 exam.