Chapter 25
| IP Interface Commands
IPv4 Interface
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input errors
9897 output
Console#
traceroute
This command shows the route packets take to the specified destination.
Syntax
traceroute
host
host
- IP address or alias of the host.
Default Setting
None
Command Mode
Privileged Exec
Command Usage
◆
Use the
traceroute
command to determine the path taken to reach a
specified destination.
◆
A trace terminates when the destination responds, when the maximum
timeout (TTL) is exceeded, or the maximum number of hops is exceeded.
◆
The traceroute command first sends probe datagrams with the TTL value
set at one. This causes the first router to discard the datagram and return
an error message. The trace function then sends several probe messages
at each subsequent TTL level and displays the round-trip time for each
message. Not all devices respond correctly to probes by returning an
“ICMP port unreachable” message. If the timer goes off before a response
is returned, the trace function prints a series of asterisks and the “Request
Timed Out” message. A long sequence of these messages, terminating
only when the maximum timeout has been reached, may indicate this
problem with the target device.
◆
If the target device does not respond or other errors are detected, the
switch will indicate this by one of the following messages:
■
* - No Response
■
H - Host Unreachable
■
N - Network Unreachable
■
P - Protocol Unreachable
■
O -Other
