CompTIA Network+ (N10-009)Networking ConceptsMedium
A workstation is manually configured with a valid IP address, subnet mask, and DNS server. Users can access other devices on the local subnet but cannot reach any external websites. Which missing configuration setting most likely explains this issue?
- ADefault gateway
- BLoopback address
- CMAC address
- DDHCP lease time
Show answer & explanationAnswer & explanation
Correct answer: A. Default gateway
The default gateway is the router interface a device uses to send traffic destined for networks outside its local subnet. Without it, a host can only communicate with devices on its own subnet, matching the described symptoms.
Why the other options are wrong
- B. The loopback address (127.0.0.1) is used for internal self-testing, not external routing.
- C. The MAC address is a hardware identifier and does not affect Layer 3 routing to external networks.
- D. DHCP lease time affects automatic address renewal, not manual configuration issues.
Default Gateway
The IP address of the router interface that a host uses to forward traffic destined for networks outside its own local subnet.
- Required for inter-network communication
- Missing gateway causes local-only connectivity
- Configured manually or via DHCP option 3
Memory trick: No gateway, no getaway — traffic stays trapped on the local subnet.