How to Use the Traceroute Command
provided by http://www.mediacollege.com
Traceroute is a command which can show you the path a packet of information takes from your computer to one you specify. It will list all the routers it passes through until it reaches its destination, or fails to and is discarded. In addition to this, it will tell you how long each 'hop' from router to router takes.
In Windows, select Start > Programs > Accessories > Command Prompt. This will give you a window like the one below.
Enter the word tracert, followed by a space, then the domain name.
The following is a successful traceroute from a home computer in Louisville Kentucky to the Evct Hosting Main Webservers:
Firstly it tells you that it's tracing the route to mediacollege.com, tells you the IP address of that domain, and what the maximum number of hops will be before it times out.
Next it gives information about each router it passes through on the way to its destination.
1 is the internet gateway on the network this traceroute was done from
2 is the ISP the origin computer is connected to (insight cable)
3 is also on the (insight cable)
4 (Insight)
5 - 9 are all routers on the Level 13 network
10-12. Finally hitting our providers network an onto Evchostings server(s) (server.evcthosting.com)
Each of the 3 columns are a response from that router, and how long it took (each hop is tested 3 times). For example, in line 2, the first try took 240ms (240 milliseconds), the second took 421 ms, and the third took 70ms.
You will notice that line 4 will 'timed out' from time to time, that is, there was no response from the router, so another one will be tried (74.128.8.33) which was successful.
You will also notice that the time it took quadrupled while passing through the HIVELOCITY>NET network.
This is extremely useful when trying to find out why a website is unreachable, as you will be able to see where the connection fails. If you have a website hosted somewhere, it would be a good idea to do a traceroute to it when it is working, so that when it fails, you can do another traceroute to it (which will probably time out if the website is unreachable) and compare them. Be aware though, that it will probably take a different route each time, but the networks it passes through will generally be very similar.
If the example above had continued to time out after line 9, you could suspect that global-gateway.co.nz was the problem, and not mediacollege.com.
If it timed out after line 1, you would know there was a problem connecting to your ISP (in this case you would not be able to access anything on the internet).
It is generally recommended that if you have a website that is unreachable, you should use both the traceroute and ping commands before you contact your ISP to complain. More often that not, there will be nothing to your ISP or hosting company can do about it.
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