What is a Traceroute?
If you've ever had the unfortunate experience of your website being unavailable online, you'd know how frustrating it can be. This situation is made even worse when friends, relatives and your hosting company all claim they can see your website!
Often, the best way to pinpoint problems like this is to run a "traceroute" to check if there are any bottlenecks in your connection to the site.
So what does a traceroute do?
Any time you view a website, data has travel between your computer and the website. The path this data takes is known as the route.
Traceroute is a tool that allows you to trace exactly where this data is going, and how long it is taking.
Where does the data go?
To use a transport analogy... Most people don't drive in a straight line from their house to their local shop. Maybe you'll have to turn left out of your driveway, take a right at the traffic lights, take another left and then hang a right at the sports shop.
The same applies when you visit a website. Because you don't have a single cable running from your computer to the web server, the path the data takes to get to you can be quite complex.
Here is an example traceroute to google.com:
The first 'hop' (192.168.0.1) is to a local wireless router. You may see something similar in your own traceroutes, depending on how you connect to the internet. From here, the data travels via telstraclear.net's network, through the "Reach" network in the US and ultimately to Google.
Each hop represents a different router, gateway or switch that your data has to travel through. Think of these like intersections, which each try to divert your data the fastest possible route towards the final destination.
The measurement shown at each stage is the time taken in milliseconds ("ms") to connect with that 'node'. You will see that the biggest jump comes at hop 7, when the data has to cross the Pacific Ocean. It is this information that can be useful in tracking whether your data is being held up.
You may also see asterisks in the output, which indicate that no response was received. The asterisk at hop 9 in the example above denotes that this computer received no response from "Google.peer.wil03.net.reach.com" one time out of three tries.
"I can see other websites, so it's not an ISP issue!"
This is a common assumption made by many people. The internet is such a complex network of systems however that it is possible for a single ISP to have issues connecting with a particular website.
The path data takes from any given location to our servers will almost always differ when compared to data from other locations, which is why we may ask for a traceroute. The result of this may help us confirm whether there are any blockages between your computer and our servers, as we may not be able to see the same problem from our location.
How do you perform a traceroute?
In Microsoft Windows systems, you would typically open a DOS Window, or select "Run" from your start menu, type "command" and click "OK". From within the command or DOS window, you would then type "tracert exampledomain.co.nz", where exampledomain.co.nz is the domain name you're looking to trace.
To make the process even easier, there are free traceroute programs like PingPlotter available. There are also a number of graphical traceroute programs like VisualRoute available, which allow you to see the physical route your data is taking on a map.