Traceroute
Trace the network path to a destination, hop by hop.
Monitor this automatically
NetTests can run this check on a schedule, preserve historical results, compare changes over time, and alert you the moment something breaks.
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What does traceroute show?
Traceroute reveals the sequence of routers (hops) a packet passes through to reach its destination, plus the round-trip time to each one. It's the standard tool for diagnosing where in the network path latency or packet loss is occurring.
How does traceroute work?
It sends packets with an incrementing TTL (Time To Live). Each router decrements the TTL and, when it hits zero, returns an ICMP Time Exceeded message. By starting at TTL=1 and increasing, traceroute collects a reply from each successive hop, building up the full path.
What does * * * mean on a hop?
Three asterisks mean no reply arrived within the timeout for that hop. This is common when a router is configured to drop or not respond to TTL-exceeded messages for security or performance reasons. It doesn't necessarily mean the path is broken — if the next hops and the final destination reply, traffic is flowing through.
How do I identify where packet loss or latency is introduced?
Look for the first hop where RTT jumps sharply or where * * * appears and the following hops also show loss or high latency. A single silent hop is usually just a router that filters ICMP; sustained loss from a hop onward points to congestion or a routing problem at that link.
What is the difference between traceroute and MTR?
Traceroute takes a single snapshot of the path. MTR (Network Path Monitor) runs continuously and builds per-hop statistics — average RTT, packet loss percentage, jitter — over many probe cycles. MTR is more reliable for spotting intermittent issues that a one-shot traceroute would miss.