HP ProCurve Management And Configuration Manual page 647

At hop 3, the first and
third probes timed out
but the second probe
reached the router.
All further probes
within the maxttl
timed-out without
finding a router or the
destination IP
address.
Figure C-30. Example of Traceroute Failing to Reach the Destination Address
Timeouts (indicated by one asterisk per probe, per hop; refer to figure
■
C-29, above.)
Unreachable hosts
■
■ Unreachable networks
■ Interference from firewalls
Hosts configured to avoid responding
■
Executing traceroute where the route becomes blocked or otherwise fails
results in an output marked by timeouts for all probes beyond the last detected
hop. For example with a maximum hop count of 7 (maxttl = 7), where the route
becomes blocked or otherwise fails, the output appears similar to this:
An asterisk indicates a timeout
without finding the next hop.
Troubleshooting
Diagnostic Tools
C-63