Cisco Certified Support Technician (CCST) NetworkingNetwork AccessMedium
A network administrator is troubleshooting a connectivity issue for a workstation connected to a Cisco switch. The workstation can ping other devices on the same VLAN, but it cannot reach devices on a different VLAN. The switch is configured for inter-VLAN routing, and the router is confirmed to be operational. Which of the following is the most likely cause of the problem?
- AThe workstation's duplex setting is mismatched with the switch port.
- BThe workstation's network adapter is faulty.
- CThe workstation has an incorrect default gateway configured.
- DThe switch port connected to the workstation is configured as a trunk port.
Show answer & explanationAnswer & explanation
Correct answer: C. The workstation has an incorrect default gateway configured.
If a workstation can communicate within its own VLAN but not with other VLANs, it suggests that its Layer 2 connectivity is fine, but it cannot reach the router responsible for inter-VLAN routing. An incorrect default gateway would prevent the workstation from sending traffic to other subnets/VLANs.
Why the other options are wrong
- A. Duplex mismatch would typically cause slow performance or connectivity issues even within the same VLAN, not just inter-VLAN.
- B. A faulty network adapter would likely prevent any network communication, including within the same VLAN.
- D. A workstation's access port should not be configured as a trunk port; this would prevent it from communicating properly, but the symptom of being able to ping within its own VLAN suggests the port is generally working for its VLAN.
Default Gateway
The IP address of the router interface on a local network segment that acts as a forwarding host to other network segments or the internet.
- Required for inter-VLAN/inter-subnet communication
- Must be on the same subnet as the host
- Traffic to non-local destinations is sent here
Memory trick: Gateway is the bridge to other VLANs.