IP Utils: Traceroute


Use the traceroute command to trace the route of a packet from the source host to a remote destination. A standard IP debugging utility, traceroute reports each gateway it encounters - the actual route a packet takes - on its path from source to destination. The command works by sending a series of probe packets out to a specified host, with each series incrementing the time-to-live (TTL) value by 1. The TTL value equals the number of hops the probe is allowed to take before the probe expires. If a probe is received by a router and has an expired TTL, the router sends back an ICMP Time Exceeded Message. The traceroute command then increments TTL by one and resends the probe. This time, it passes the previous router, but expires at the next router down the path. This process continues until the probe reaches the host.

This command can trace a path to either another virtual router within the same chassis, a virtual router in another system, or a physical router. The host that receives the query responds as if to a physical router, and the resulting path is from there to the virtual router. Each virtual router configured within the Sun Secure Application Switch can query and respond to the traceroute command. You can send multiple traceroute requests to the same destination.

Access mode

exec

Syntax

vSwitch-name vRouter-name traceroute

Arguments

Field Name Description
host ipAddress Target host.
srcAddr ipAddress Optional: Source address.
timeout integer Optional: Timeout in milliseconds for each probe.

The default setting is "3000".
count integer Optional: Number of probes to send per hop.

Valid values are from 1 to 10; the default setting is "1".
minTTL integer Optional: Sets the starting TTL (Time to Live) value for the probe.

Valid values are from 1 to 255; the default setting is "1".
maxTTL integer Optional: Maximum TTL: number of hops to search for target.

Valid values are from 1 to 255; the default setting is "64".
port integer Optional: UDP destination port number for probe packets.

Valid values are from 1 to 65535; the default setting is "33434".
size integer Optional: Size of the UDP probes in bytes (not including the IP or UDP headers). Because on some systems (such as many win32 machines) IP packets with a total length that is a multiple of 256 return invalid ICMP error messages, the following sizes are not recommended: 228, 484, 740, 996, 1252.

Valid values are from 0 to 1472; the default setting is "40".