Runs from your Mac
It uses macOS’s own traceroute, so the route is the one your traffic actually takes, not one from a server somewhere else.
Every hop to a host, on a map
Trace the route from your Mac to any server and watch each router appear on the map as it answers.
| 1 | 192.168.1.1 | router.lan | 1.9 ms | LAN |
| 2 | 96.120.24.53 | — | 9.8 ms | New York, US |
| 3 | 68.85.62.121 | be-11-ar01.newyork.ny.comcast.net | 11.2 ms | New York, US |
| 4 | * | * | ||
| 5 | 4.69.211.17 | ae-2.r24.londen12.uk.bb.gin.ntt.net | 78.4 ms | London, GB |
| 6 | 17.253.31.204 | — | 80.1 ms | London, GB |
Illustration of the Traceroute view.
Hops on the map
Each router that answers appears on the map as the trace runs, joined into a route you can zoom and follow.
ICMP or UDP probes
ICMP probes (like ping) get answers from more destinations; UDP is traceroute’s classic default. Switch when a trace stalls.
Router names
Reverse DNS shows names like ae-2.r24.londen12.uk.bb.gin.ntt.net, which often hint at the city and network. Turn it off if you’d rather not query your resolver.
Choose how far
Give up after 16, 30, 48 or 64 hops. Stop a running trace at any time with ⌘.
Copy and inspect
Right-click a hop to copy its address or name, or show it on the map.
How it works
Traceroute sends probes with a growing time-to-live (TTL). Each router that drops a probe because its TTL ran out sends back an error, which reveals that router’s address and the round-trip time.
* * * means a router didn’t reply. Many routers drop these probes but still forward your traffic, so a few stars in the middle are normal.
Router locations are approximate: an address often maps to where the network is registered, not to where the router is.
Questions
Is this the same as running traceroute in Terminal?
Yes. LightAtom runs /usr/sbin/traceroute and reads its output, then adds router names, locations and the map.
Should I use ICMP or UDP probes?
Start with ICMP: more hosts answer it. If the trace stops early, try UDP, since some networks filter one kind but not the other.
Why does the trace end in stars?
The destination or the last routers ignore probes. That doesn’t mean the host is down; try the other probe protocol or a ping test.
Does reverse DNS send data anywhere?
It asks your DNS resolver for each router’s name, which shares the router addresses with that resolver. It’s on by default for traceroute; turn it off to keep router addresses from your resolver.