Tracing Unicast Routes from the CLI
Use the CLI traceroute command to display a list of routers between the Services
Router and a specified destination host. This command is useful for diagnosing a
point of failure in the path from the Services Router to the destination host, and
addressing network traffic latency and throughput problems.
The Services Router generates the list of routers by sending a series of ICMP traceroute
packets in which the time-to-live (TTL) value in the messages sent to each successive
router is incremented by 1. (The TTL value of the first traceroute packet is set to 1.)
In this manner, each router along the path to the destination host replies with a Time
Exceeded packet from which the source IP address can be obtained.
Alternatively, you can use the J-Web interface. (See “Tracing Unicast Routes from
the J-Web Interface” on page 223.)
The traceroute monitor command combines ping and traceroute functionality to
display real-time monitoring information about each router between the Services
Router and a specified destination host.
This section contains the following topics. For more information about traceroute
commands, see the JUNOS System Basics and Services Command Reference.
■Using the traceroute Command on page 237
■Using the traceroute monitor Command on page 238

Using the traceroute Command

To display a list of routers between the Services Router and a specified destination
host, enter the traceroute command with the following syntax. Table 121 on page
237 describes the traceroute command options.
user@host> traceroute host <interface interface-name> <as-number-lookup>
<bypass-routing> <gateway address> <inet | inet6> <no-resolve>
<routing-instance routing-instance-name> <source source-address> <tos number>
<ttl number> <wait seconds>
To quit the traceroute command, press Ctrl-C.
Table 121: CLI traceroute Command Options
DescriptionOption
Sends traceroute packets to the hostname or IP address you specify.
host
(Optional) Sends the traceroute packets on the interface you specify. If you do not include this
option, traceroute packets are sent on all interfaces.
interface interface-name
(Optional) Displays the autonomous system (AS) number of each intermediate hop between the
router and the destination host.
as-number-lookup
Using CLI Diagnostic Commands ■237
Chapter 12: Using Services Router Diagnostic Tools