The Traceroute tool is similar to the ping tool except that it shows the results of a ping to each router on route to its destination. Some of the advanced options of the ping tool are also offered here. The TTL (Time to Live) should be set with care. The value will determine how many hops will be evaluated. The output of the traceroute is also similar to the ping in terms of the information shown. But unlike the ping where each output shows the success at reaching the destination, the traceroute tool shows the success at reaching the router at each step along the path to the destination. The Average, Max and Min RTT (Round Trip Time) is shown, as well the number of pockets sent, received and percent received at each stage. For a more detailed explanation of the advanced parameters see the ping tools documentation above. The far right of column shows a graph of the average response time when compared to the maximum average response time. This allows for the quick identification of the slowest hop in the route.
A traceroute is said to have succeeded if the destination was reached. Just like the ping tool, failure to reach the destination does not always imply a failure. Firewalls may block ping responses after a point in the route. Administrators may also, for some reason, setup devices so they do not respond to Ping requests.
Lists of hosts to run a traceroute can be imported from a text file. Each row in the file should contain the name of the host to ping. Any number of lines can be present.
Table 6.1. Advanced Traceroute Properties
| Delay | The amount of time waited, in seconds, between each ping request sent. The RTT is usually shown in three values, the Average, the Max and the Min. If only one request is sent then the Average, Max and Min will all be the same, so as a general rule more that one ping is sent so a better idea of the effective RTT is calculated over a short period on time, and not only at one instance in time. The number of requests that will be sent on a non-continuous ping is set by the 'Attempts' option. The Delay is the amount of time between each ping request. |
| Timeout | How long to wait, in seconds, before assuming the request has failed. |
| TTL (Time to Live) | As the pocket of data sent along the network goes through a router, the TTL value contained within the pocket is reduced by one every time. Once the TTL reaches zero the router will no longer attempt to forward the pocket on to its destination, but rather abort the attempt and reply to the sender saying TTL expired. If not for the TTL feature in TCP pockets, then a ping request on a bad network could bounce around a network forever. |
| Request Size | This is the size of the pocket of data sent. |
| Attempts | The number of pockets sent in a non-continuous ping. |