What does traceroute show?
Traceroute attempts to reveal responding routers towards a target address. The ipcheck.tools online traceroute starts on our Linux server in Düsseldorf. Your browser submits the target and displays the result. To investigate a path from your home network, also measure from your own device.
How to start a useful check
- Enter a public domain or IP address. Internal targets such as
192.168.1.1are not allowed. - Select IPv4 or IPv6 when comparing the protocols separately.
- Keep the same target IP for repeated tests if DNS returns several addresses.
- Press Enter or the button, then wait for the completed or limited partial path.
How are hops discovered?
The tool sends probes with increasing TTL or hop limit. Routers may return an ICMP reply when that value expires. Those replies form the observed hop list. ipcheck.tools uses UDP probes, at most 20 hops and one probe per hop. The measurement is limited after about 25 seconds. This snapshot does not necessarily reveal every router or the return path.
What does an asterisk mean?
An asterisk means no matching reply arrived for that probe within the limit. Filtering or reply rate limits may be responsible. If subsequent hops respond, traffic has evidently continued along the path. Even a consistently incomplete route does not by itself establish that the target application is down.
Example: A gap between responding hops
The following illustration is fictional and uses reserved documentation addresses. It is not a live result.
Hop 1: 192.0.2.1 4 ms Hop 2: * no reply Hop 3: 198.51.100.1 18 ms Hop 4: 203.0.113.10 22 ms
Hop 2 is silent while later hops reply. That does not establish a broken link at hop 2. The difference between 18 and 22 ms is not a reliable measurement of the link between those routers either: each time belongs to a separate reply with its own return path.
What do “target reached” and “partial path” mean?
“Target reached” means the check recognised a completion reply matching the target. It does not confirm a working web or mail service. A partial path ends without that confirmation, perhaps because of filtering, the hop limit or the time limit. Record the result and compare another attempt rather than treating one run as a permanent state.
Which check should I use next?
For a website, the HTTP check supplies additional information. Use TCP ping to test connection setup on the required port. The ASN lookup explains networks and observed BGP neighbours; these are not measured router hops. When local and server-side results disagree, location, address family, DNS target and measurement method can explain the difference.