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7-4
MAX Administration Guide
Administering TCP/IP
Managing the Internet Protocol (IP)
Example of Traceroute command usage
For example, to trace the route to a host named
techpubs
:
ascend% traceroute techpubs
traceroute to techpubs (10.65.212.19), 30 hops MAX, 0 byte packets
1 techpubs.eng.ascend.com (10.65.212.19) 0 ms 0 ms 0 ms
Probes start with a TTL of one and increase by one until one of the following conditions
occurs:
•
The unit receives an ICMP Port Unreachable message.
The UDP port in the probe packets is set to an unlikely value, such as 33434, because the
target host is not intended to process the packets. A “port unreachable” message indicates
that the packets reached the target host and were rejected.
•
The TTL value reaches the maximum value.
By default, the maximum TTL is set to 30. Specify a different TTL by using the
-m
option.
For example:
ascend% traceroute -m 60 techpubs
traceroute to techpubs (10.65.212.19), 60 hops MAX, 0 byte packets
1 techpubs.eng.abc.com (10.65.212.19) 0 ms 0 ms 0 ms
Three probes are sent at each TTL setting. The second line of command output shows the
address of the router and round trip time of each probe. If the probe answers come from
different gateways, the address of each responding system is shown. If there is no response
within a three second timeout interval, the command output is an asterisk. Table 7-2 describes
the annotations that can appear after the time field in a response.:
datasize
Sets the size of the data field of the UDP probe datagram sent by
Traceroute. The default is 0. This results in a datagram size of 38
bytes (a UDP packet carrying no data).
Table 7-1. Traceroute command syntax elements (continued)
Element
Definition
Table 7-2. Time field responses and annotations
Annotation
Definition
!H
Host reached.
!N
Network unreachable.
!P
Protocol unreachable.
!S
Source route failed. Might indicate a problem with the associated
device.
!F
Fragmentation needed. Might indicate a problem with the associated
device.