3Com CoreBuilder 3500, Справочник по командам

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182 C
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management ip
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traceRoute
Traces a route to a destination using the default traceRoute options.
Valid Minimum Abbreviation
m ip t
Important Considerations
■
TraceRoute information includes all of the nodes in the network
through which a packet passes to get from its origin to its destination.
It uses the IP time-to-live (TTL) field in User Datagram Protocol (UDP)
probe packets to elicit an Internet Control Message Protocol (ICMP)
Time Exceeded message from each gateway to a host.
■
To change the default traceRoute options, use the
management ip
advancedTraceRoute
command.
■
You can either supply the host name or IP address as part of the
command string, or you can supply the information at the prompt.
■
When you specify a host name, the host name and its associated IP
address
must
be configured on a network name server. Also, you must
add the IP address on the name server to the list of name server
addresses that are associated with the network domain name. See
Chapter 16 for more information about
ip dns
commands.
■
To track the route of an IP packet, traceRoute launches UDP probe
packets with a small TTL value and then listens for an ICMP Time
Exceeded reply from a gateway. Probes start with a small TTL of 1 and
increase the value by 1 until one of the following events occurs:
■
The system receives a Port Unreachable message, indicating that
the packet reached the host.
■
The probe exceeds the maximum number of hops (default
30
).
■
At each TTL setting, the system launches three UDP probe packets,
and the traceRoute display shows a line with the TTL value, the
address of the gateway, and the round-trip time of each probe. If a
probe answers from different gateways, the traceRoute feature prints
the address of each responding system. If no response occurs in the
3-second timeout interval, traceRoute displays an asterisk (*) for that
probe.