traceroute

traceroute

Syntax Description

Examples

Related Commands

traceroute

The traceroute command directs the device to send UDP test packets to each intermediate hop along the route to the requested IP address or host name.

This command is used for network testing when there are difficulties in reaching a selected host. Each node along the route to the host is probed with a test UDP packet, and should return an ICMP packet to the device. The device displays round-trip times and IP addresses/host names for each node. If a node does not respond within the timeout period, a timeout is indicated in the display by an asterisk.

traceroute {destination_address | host_name} [nonames] [probes #probes] [timeout timeout] [hops #hops] [source address {source_address | {Ethernet | WAN} slot:port[.sub-interface]}]

Syntax Description

destination_address | host_name

This required parameter is used to indicate the host name or IP address of the ultimate destination. It can be entered either as a numerical IP address (e.g., 10.1.2.3) or a host name (e.g., hal.acme.com) if a Domain Name Server has been configured (see the Domain Name Server section).

nonames

This optional keyword directs the command to print out only numerical IP addresses for each node along the route. If this keyword is not present, both the IP address and the host name of each intermediate hop will be displayed.

probes #probes

This optional keyword specifies the number of probes to be launched at each intermediate machine. Valid probe counts are 1, 2, or 3. The default is 3 probes.

timeout timeout

This optional keyword specifies the amount of time which the device will wait before declaring that the response has timed out. The default timeout is 1 second. If excessive timeouts are occurring during the traceoute, the process can be terminated by entering a <CTRL-C> at the keyboard.

hops #hops

This optional keyword specifies the maximum number of hops the traceroute command will use in an attempt to reach the end destination. The default is 40 hops. This should be sufficient for most applications.

sourceaddress {source_address | {Ethernet | WAN} slot:port[.sub-interface]}

This keyword specifies which port or address is to be used as the origin of the outbound packet. The value must be an IP address of an associated interface or a port name on the device. If no sourceaddress is specified, the device will, by default, use the address of the outbound interface as its source. This option allows packets that are sent out via traceroute to be correctly answered. This option allows the traceroute command to function over the Internet from a device which uses a private, unroutable WAN address. An example is the case where a Frame Relay link is using a private IP address on the WAN and the user wants to traceroute across that interface to test connectivity out to the Internet.

destination_address \| host_name	This required parameter is used to indicate the host name or IP address of the ultimate destination. It can be entered either as a numerical IP address (e.g., 10.1.2.3) or a host name (e.g., hal.acme.com) if a Domain Name Server has been configured (see the Domain Name Server section).
nonames	This optional keyword directs the command to print out only numerical IP addresses for each node along the route. If this keyword is not present, both the IP address and the host name of each intermediate hop will be displayed.
probes #probes	This optional keyword specifies the number of probes to be launched at each intermediate machine. Valid probe counts are 1, 2, or 3. The default is 3 probes.
timeout timeout	This optional keyword specifies the amount of time which the device will wait before declaring that the response has timed out. The default timeout is 1 second. If excessive timeouts are occurring during the traceoute, the process can be terminated by entering a <CTRL-C> at the keyboard.
hops #hops	This optional keyword specifies the maximum number of hops the traceroute command will use in an attempt to reach the end destination. The default is 40 hops. This should be sufficient for most applications.
sourceaddress {source_address \| {Ethernet \| WAN} slot:port[.sub-interface]}	This keyword specifies which port or address is to be used as the origin of the outbound packet. The value must be an IP address of an associated interface or a port name on the device. If no sourceaddress is specified, the device will, by default, use the address of the outbound interface as its source. This option allows packets that are sent out via traceroute to be correctly answered. This option allows the traceroute command to function over the Internet from a device which uses a private, unroutable WAN address. An example is the case where a Frame Relay link is using a private IP address on the WAN and the user wants to traceroute across that interface to test connectivity out to the Internet.

Examples

The following illustrates a traceroute to the host "hal.acme.com" using the default parameters. The round-trip time is reported in increments of 16 ms, anything less will be reported as 0 ms. Note that node 4 did not respond to any of the UDP packets in the allotted time. This could indicate excessive congestion on that node at the time of the probes.

MyRouter> tr hal.acme.com                                   
        Traceroute to hal.acme.com                                          
        IP Address = 10.1.2.3                                          
        3 probes per hop, 1 sec timeout, 40 hops max                      
  1  12.5.6.8 (saturn.abc.com)  16ms 16ms 0ms
  2  13.80.3.18 (neptune.def.com)  128ms ** 64ms
  3  4.100.6.30 (mercury.ghi.com)  160ms 340ms 176ms
  4  ********** ** ** **
  5  138.42.2.1 (pluto.jkl.com)  48ms 192ms 208ms
     6     10.1.2.3 (hal.acme.com)  48ms 64ms 48ms                                 
     Destination reached in 6 hops

If there is no Domain Name Server, the name lookup can be disabled with the nonames option. The timeout can be increased in an attempt to get a response from node 4:

MyRouter> tr hal.acme.com nonames probes 2 timeout 3 hops 10                       
        Traceroute to hal.acme.com                                           
        IP Address = 10.1.2.3                                            
        2 probes per hop, 3 sec timeout, 10 hops max                      
  1  12.5.6.8  16ms 16ms
  2  13.80.3.18  128ms 64ms
  3  4.100.6.30  160ms 176ms
  4  15.3.80.4  1600ms 1760ms
  5  138.42.2.1  192ms 208ms
   6  10.1.2.3  48ms 64ms                                              
     Destination reached in 6 hops

Note If more processing is enabled, output will stop when a screenful of data has been output. If a lot of output is expected, more processing can be disabled using the set terminal nomore command.

Related Commands

Command Description

configure Domain Name Server

Configures a DNS for the concentrator

set terminal

Sets Terminal parameters

Command	Description
configure Domain Name Server	Configures a DNS for the concentrator
set terminal	Sets Terminal parameters

Table of Contents

traceroute

Syntax Description

Examples

Related Commands