Use ping for a quick end-to-end baseline, traceroute or Windows PathPing to inspect the route, and MTR to watch that route over repeated probes. If you need to test loss under controlled traffic, use iPerf3 between systems you control. Use Wireshark or TShark for packet-level evidence, and add Windows Pktmon when you need to locate drops inside a Windows host.
No single tool answers every question. A missing reply from an intermediate router may mean that router filters or rate-limits diagnostic probes—not that it is dropping ordinary traffic. Confirm suspected loss at the final destination and, when possible, correlate it with a controlled traffic test or packet capture.
What packet-loss test should you run first?
Start with a low-rate ping to the affected destination. It is quick and establishes whether replies are missing end to end, but it does not identify where along the path a problem occurs or explain what caused it. If ping shows loss, compare the route with MTR or traceroute; if symptoms happen under load, use iPerf3 between endpoints you control. Capture the test with Wireshark or TShark when you need packet-level evidence. On Windows, Pktmon can help determine whether drops occur locally.
Keep the comparison fair: test the same destination, from the same source, and over comparable periods. Record the time, probe or traffic type, packet size, rate, and duration. A short idle test and a sustained loaded test answer different questions.
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Choose among the six tools
| Tool | Scope | Traffic or evidence | Best use |
|---|---|---|---|
| Ping | End to end | ICMP echo requests and replies | Fast reachability and loss baseline |
| Traceroute / Windows PathPing | Hop by hop, plus destination result | Route probes and response behavior | Seeing where a path symptom first appears |
| MTR | Repeated, hop-by-hop path view | Repeated ping-style measurements and route tracing | Observing loss and latency over time |
| iPerf3 | Between a test client and server you control | Controlled TCP or UDP traffic | Testing behavior under a chosen traffic load |
| Wireshark / TShark | Traffic visible at the capture endpoint | Packet-level analysis and statistics | Investigating retransmissions, sequence behavior, and timing |
| Windows Pktmon | Local Windows host | Packet traces, loss statistics, and local drop attribution | Finding drops associated with local reasons or code locations |
1. Ping: establish an end-to-end baseline
Ping sends ICMP echo requests and records replies and round-trip times. Its loss percentage is a useful first signal: it tells you whether the destination answered all probes during that sample. It does not show which intermediate link caused a missing reply, and it tests ICMP rather than every application protocol.
How to use the result
- Run a repeatable series rather than relying on one request; note the count, interval if configurable, and test duration.
- Record replies, round-trip time, and reported loss percentage. Repeat during the period when the problem occurs.
- Compare the destination result with path tools before attributing loss to a particular network hop.
A destination that replies to every probe in an idle sample is not proven healthy under load. Conversely, missing ICMP replies are evidence about those probes, not automatically proof that a TCP or UDP application flow loses the same packets.
2. Traceroute or Windows PathPing: inspect the route
Traceroute-style tools send probes that elicit responses from routers along the route. Windows PathPing combines route inspection with repeated measurements. These tools can show where latency or missing responses first appear, which helps narrow the next investigation.
Do not treat a nonresponsive intermediate hop as conclusive packet loss. Routers may filter or rate-limit diagnostic traffic while continuing to forward transit traffic. Compare the suspicious hop with later hops and, especially, the final destination. If an intermediate hop reports missing replies but the destination does not, the intermediate response behavior alone does not establish end-to-end loss.
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What to record
- The destination and time of the run.
- The first hop where latency or missing diagnostic replies appear.
- Whether the same symptom continues at the destination.
3. MTR: watch a path over repeated probes
MTR combines repeated ping-style measurements with route tracing. Rather than showing only one path snapshot, it can help you observe loss and latency at each hop over time. Microsoft Ethr also documents an MTR test specifically for loss and latency.
Use MTR when a brief traceroute does not capture an intermittent symptom. Let observations accumulate during the affected period, then compare hop behavior with the destination. As with traceroute, missing replies at one router can reflect probe filtering or rate limiting. A per-hop percentage is not by itself proof that the router is discarding transit packets; destination behavior and corroborating tests matter.
4. iPerf3: test controlled traffic and load
iPerf3 measures traffic between a client and a server that you control, making it useful when you need to test more than idle reachability. Prefer UDP when the question is direct packet-loss percentage and jitter: the iPerf project documents that UDP reports loss and jitter, whereas TCP does not report loss directly to the user.
Run tests at several traffic rates and durations. A low-rate run can establish a baseline; progressively higher rates can reveal whether symptoms emerge as offered traffic increases. Keep the server and client endpoints, packet size, rate, duration, and direction consistent when comparing runs. Do not infer the condition of an unrelated route from a test between different endpoints.
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Why UDP and TCP tell different stories
UDP does not provide acknowledgment or retransmission itself. A UDP application can therefore experience packet loss without a transport-layer recovery signal. TCP detects loss and retransmits, so application-visible behavior may include delays or reduced throughput rather than a direct loss percentage exposed by the protocol. For a direct loss measurement, use iPerf3 UDP and record its reported loss and jitter; TCP remains relevant when you want to observe behavior under TCP traffic.
5. Wireshark or TShark: inspect packet-level evidence
Wireshark is a packet analyzer with protocol statistics; TShark provides command-line packet analysis. A capture at an endpoint can help you inspect retransmissions, sequence behavior, conversations, and time-series statistics. Use this depth when a percentage alone does not explain what the endpoint observed.
TShark can calculate ICMP request and reply counts, loss, percentage loss, and latency statistics including minimum, maximum, mean, median, and sample standard deviation. Those measurements describe the captured traffic and vantage point. A capture at one endpoint cannot, on its own, identify every device or link outside that endpoint.
When investigating an application, capture the relevant test traffic and examine its protocol behavior. TCP retransmissions are evidence that the TCP sender is recovering from missing or delayed data; UDP has no transport-layer acknowledgment or retransmission by itself. Correlate packet observations with the test interval and the corresponding ping or iPerf3 run rather than treating unrelated capture events as proof of the same incident.
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6. Windows Pktmon: investigate drops on a Windows host
Pktmon captures packet traces, reports packet-loss statistics, and can attribute local packet loss to specific reasons and code locations. It is the most relevant of these six tools when your question is whether loss is occurring inside a Windows system rather than somewhere along the wider network path.
Microsoft recommends combining Pktmon traces with Wireshark analysis when diagnosing Windows loss. Use Pktmon to gather local trace and attribution evidence, then inspect the trace in Wireshark when protocol-level analysis is useful. Treat host-local findings separately from end-to-end measurements: a local drop and a path symptom can coexist, but one does not automatically explain the other.
A practical packet-loss troubleshooting sequence
- Establish a baseline. Run a low-rate ping to the affected destination and record replies, loss, and round-trip time.
- Check the path. Run MTR or traceroute; on Windows, PathPing is another option. Note where symptoms first appear, and check whether they persist at the destination.
- Reproduce the conditions. If the problem occurs under load, run iPerf3 UDP between endpoints you control. Test multiple rates and durations, recording loss, jitter, bitrate, packet size, and duration.
- Gather packet evidence if needed. Capture the relevant test with Wireshark or TShark to examine retransmissions, sequence behavior, conversations, and timing.
- Check the local Windows path when applicable. Add Pktmon if you need to investigate drops associated with the Windows stack, driver, or interface, and analyze its trace with Wireshark when helpful.
- Compare like with like. Align destination, direction, time window, endpoints, and traffic conditions before deciding whether two tools corroborate one another.
How to avoid false conclusions
- Intermediate hop does not reply: this can result from filtering or rate limiting of diagnostic probes. Check later hops and the destination before calling it transit loss.
- Ping is clean but an application still stalls: ping is an ICMP baseline, not a full test of the application’s traffic. Reproduce the issue with controlled traffic or capture the application flow.
- Loss appears only under load: an idle ping cannot rule out a load-related problem. Use iPerf3 between controlled endpoints and compare more than one rate and duration.
- UDP symptoms have no recovery signal: UDP does not acknowledge or retransmit packets on its own. Measure UDP loss and jitter directly rather than expecting TCP-style recovery evidence.
- TCP does not show a direct user-facing loss percentage: TCP detects and retransmits lost data. Use packet analysis for retransmission evidence and UDP iPerf3 when a direct loss percentage is the objective.
- Local and network symptoms are mixed: an end-to-end probe cannot attribute a drop to a Windows component. Use Pktmon for local attribution and compare its trace with endpoint and path measurements.
Performance, reliability, and cost considerations
Ping and MTR are lightweight diagnostic probes, while iPerf3 intentionally generates traffic. Keep the initial probe rate low, and increase test load deliberately; a high-rate traffic test can change the conditions you are trying to measure. Packet captures and local tracing provide more evidence to interpret, but require careful alignment with the test interval and endpoints.
Reliability comes from corroboration, not from trusting one percentage in isolation. Repeat tests during the reported symptom, compare destination results to intermediate-hop behavior, and use the tool whose scope matches the question: end-to-end reachability, route symptoms, controlled-load performance, packet behavior, or local host drops. The tools described here have no prices stated in the cited project and vendor documentation summarized above.
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Frequently Asked Questions
Does a missing ping reply prove that a packet was lost?
It proves that the ICMP reply was not observed in that test. It does not alone identify where the problem occurred or establish that application traffic was lost.
Which tool can show packet loss at each hop over time?
MTR combines repeated ping-style measurements with route tracing, so it can show loss and latency observations across hops over time. Interpret intermediate-hop results alongside the destination.
Which of the six tools can attribute drops inside Windows?
Pktmon can capture traces, report packet-loss statistics, and attribute local drops to reasons and code locations.
Quick Recap
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