3Com 3C13618 Command Reference Manual page 88

3Com Router Command Reference Guide — V1.00
first_TTL: Specifies the first TTL, ranging from 0 to maximum TTL.
-m: To test if the –m switch is correct.
max_TTL: Specifies a maximum TTL, which is greater than the initial TTL.
-p: To test if the –p switch is correct.
port: The port number of the destination host, an integer. Generally, you do not have
to modify this parameter.
-q: To test if the –q switch is correct.
nqueries: The number of test data packets sent each time, an integer greater than 0.
-w: To test if the –wf switch is correct.
timeout: Specifies the timeout value for the IP packet in seconds, an integer greater
than 0.
Description
Using tracert command, you can view the path from the source address to the
destination address.
If not specified, the parameters are set as follows:
first_TTL: 1.
max_TTL: 30.
port: 33434.
nqueries: 3.
timeout: 5s.
The tracert command can be used to test the gateways through which the data
packets travel from the source host to the destination host. It can be used to check if
the network connection is reachable and to analyze where does the fault occur.
The procedure of executing the tracert command is as follows.
First, send a data packet whose TTL is 1, so that the first hop feeds back a ICMP
error message indicating that this data packet can not be sent because of TTL timeout.
Then this data packet is retransmitted with TTL being 2. Again, the second hop feeds
back a TTL timeout message. This process continues until the packet reaches the
destination. The purpose of executing these processes is to record the source
address for each ICMP TTL timeout message, and to provide the path through which
an IP packet travels before reaching the destination.
After identifying a fault in the network through using the ping command, you can
locate the fault by using the tracert command.
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