http://en.wikipedia.org/wiki/Traceroute traceroute is a computer network tool used to determine the route taken by packets across an IP network. An IPv6 variant, traceroute6, is also widely available. The traceroute tool is available on practically all Unix-like operating systems. Variants with similar functionality are also available, such as tracepath on modern Linux installations and tracert on Microsoft Windows operating systems. Windows NT-based operating systems also provide pathping, which provides similar functionality. Traceroute is often used for network troubleshooting. By showing a list of routers traversed, it allows the user to identify the path taken to reach a particular destination on the network. This can help identify routing problems or firewalls that may be blocking access to a site. Traceroute is also used by penetration testers to gather information about network infrastructure and IP ranges around a given host. It can also be used when downloading data, and if there are multiple mirrors available for the same piece of data, one can trace each mirror to get a good idea of which mirror would be the fastest to use.
