traceroute

This command traces the network path to a target host.

Syntax

Trace the path by IP address.
traceroute address [local_address]
Trace the path by host name.
traceroute host [IP-version] [local_address]

Parameters

address
Specifies the IP address of the target.
host
Specifies the host name of the target.
IP-version
Optional: Identifies the IP version to use when resolving an ambiguous host name to an IP address. An ambiguous host name occurs when the DNS publishes an IPv4 address and an IPv6 address. If not specified, resolves to the preferred IP version as defined by the ip-preference command in DNS Settings mode.
-4
Identifies the target as an IPv4 host.
-6
Identifies the target as an IPv6 host.

This parameter applies to ambiguous host names only. Although you specify -6, the output will show IPv4 output if the DNS published an IPv4 address only. Conversely, if you specify -4 and the DNS publishes an IPv6 address only, the output will show IPv6 output.

local_address
Optional: Specifies the IP address of a local interface to use for the traceroute.

Guidelines

The traceroute command traces the route that packets actually take to their target host. The output shows the IP address of the hops (for example, gateway or routers) and the round trip time.

You must be logged in as the admin user to use this command.

The traceroute command is intended for use in network testing, measurement, and management. In other words, use this command for manual fault isolation. Because of the load it imposes on the network, do not use this command during typical operations or from automated scripts.

While the ping command confirms IP network reachability, you cannot pinpoint and improve some isolated problems. Consider the following situation:
  • When there are many hops (for example, gateways or routers) between the appliance and the target host, and there seems to be a problem somewhere along the path. The target host could have a problem, but you need to know where a packet is actually lost.
  • The ping command hangs up and provides no reason for a lost packet.

The traceroute command can inform you where the packet is located and why the route is lost. If your packets must pass through routers and links, which belong to and are managed by other organizations or companies, it is difficult to check related routers. The traceroute command provides a supplemental role to the ping command.

A packet capture can be used to verify the local IP address used to perform a route trace.

Examples

The following command can be used to trace the route to the remote server host123. In this scenario, the routing table selects interface mgt0 and the appliance sends the request from the primary IP address of the interface, 192.0.2.33.

mqa(config)# traceroute myhost123
The following command repeats the same test using the secondary IP address associated with the interface:
mqa(config)# traceroute myhost123 192.0.2.35