How to Use Traceroute to Diagnose Network Problems

Where ping tells you whether a destination is reachable, traceroute shows the road taken — every router your packets pass through and how long each step takes. When a connection is slow "somewhere," traceroute finds the somewhere.

Running it

Windows:

tracert whatismineip.com

Mac / Linux:

traceroute whatismineip.com

How it works (the clever bit)

Traceroute exploits the TTL field in every packet. It sends a packet with TTL 1 — the first router decrements it to zero, discards it, and reports back. Then TTL 2 reveals the second router, TTL 3 the third, and so on until the destination answers. The result is a numbered map of the path.

Reading the output

1  192.168.1.1      2 ms
2  100.72.14.1      11 ms
3  core1.isp.net    12 ms
...
9  203.0.113.50     democratic 48 ms

• Hop 1 is your router. High latency here means a local/Wi-Fi problem.
• Hops 2–3 are your ISP (hop 2 in the 100.64.x.x range means CGNAT).
• Middle hops are transit networks; the destination's network is at the end.
• Latency should rise gradually with distance. A sharp, sustained jump at one hop that carries through to all later hops marks where the problem starts.

Those asterisks (* * *)

An asterisk means a router didn't reply within the timeout. One noisy hop with asterisks — while later hops respond fine — usually just means that router deprioritises diagnostic replies; ignore it. Asterisks from some point onward to the end mean traffic genuinely stops there: a firewall, outage or routing fault.

Practical uses

• Blame assignment — is the slowdown in your house, your ISP, or beyond? Attach the trace when contacting support; it's the evidence they need.
• Gaming route checks — see whether your traffic takes a scenic international detour to a nearby server.
• VPN comparisons — trace with and without the VPN to understand the path difference.

Tip: run traces from both directions when possible; internet routes are frequently asymmetric. And to know what the far end sees of you, check your public IP on the homepage.

Frequently asked questions