A technician runs a traceroute to a company's public web server and observes low, consistent latency at every intermediate hop along the path. However, the final hop (the destination server itself) shows latency spikes of over 800 ms on some probes. Other services hosted on the same subnet as the web server respond quickly. What does this result most likely indicate?
- AAn MTU mismatch exists between the client and the destination
- BThe web server itself is under heavy load or has an application-level performance issue, not the network path
- CA routing loop exists somewhere along the path to the destination
- DThe ISP is throttling traffic to the destination's subnet
Show answer & explanationAnswer & explanation
Correct answer: B. The web server itself is under heavy load or has an application-level performance issue, not the network path
Because latency is low and stable across every intermediate hop but spikes only at the final destination, and other hosts on the same subnet respond normally, the network path is healthy. This points to a host-specific issue on the web server itself — such as high CPU load, resource exhaustion, or an application bottleneck — rather than a network transport problem.
Why the other options are wrong
- A. MTU mismatches typically cause fragmentation/drops, not latency spikes limited to the final hop.
- C. A routing loop would cause increasing latency or TTL expiration across multiple hops, not just the final destination.
- D. ISP throttling would likely affect the entire subnet, but other hosts on that subnet respond quickly.
Isolating Latency to the Destination Host
When traceroute shows healthy latency at all intermediate hops but spikes only at the final destination, the problem is likely on the destination host itself rather than in the network path.
- Compare latency across hops to isolate where delay is introduced.
- If only the last hop is affected and neighbors are fine, suspect the host, not the path.
- Common host-side causes: CPU load, disk I/O, or application bottlenecks.
Memory trick: 'If the road is smooth but the destination is slow, blame the house, not the highway.'