Using traceroute

Background

The Internet is a global network comprised of many independently owned and operated networks. There are many points within the network at which problems may arise.

Data follows a specific path as it travels on the Internet between your computer and the Korax network. Each point along that path represents a router. A router is a network device which routes packets between different networks. Each router is owned and controlled by a different company, operating its own network on the Internet. These points are all potential sources of network issues.

The smallest unit of data traveling on the Internet is called a "packet". It is possible to follow the actual route a single packet takes from your computer to the Korax network. Along the way, you can discover any possible sources of trouble.

Using traceroute on Windows

Traceroute is a small program that follows the route a packet takes from your computer to any Internet host, including your website hosted at Korax. As it moves, or "hops" from one router to the next along the network path, it measures the round-trip time between your computer and that particular hop in milliseconds. On Windows, follow these steps to run traceroute.

1. From the "Start" menu, select "Run".
2. Type cmd and click OK.
3. Type tracert www.example.com and press Enter. Replace www.example.com with your own website address.

You'll see output that looks similar to this: A traceroute report will display the domain name and IP address of each hop, plus three samples of the time, measured in milliseconds, it took to reach that hop and receive a response. It also counts the number of hops between you and the host you are tracing to. Each hop is displayed on its own numbered line.

The above output indicates that it took eight hops to reach the website www.example.com, hosted on server vs1.korax.net, and the round-trip time ranged between ten and fourteen milliseconds.

Understanding traceroute's output

Generally, within North America it should take a packet less than one hundred milliseconds to make the trip. Anything significantly higher than that may cause a noticeable degradation in network performance.

When using traceroute, examine each line of data. If the report indicates that all hops after a certain point are taking 200 or more milliseconds to complete, that point on the network path is likely experiencing congestion problems that are creating high latency. However, it is not unusual for some hops to show high latency values, yet not be experiencing any problems. Several traceroutes in a row must be run in order to accurately show the condition of the network.

If a sample could not be taken at all, traceroute will show an asterisk. If all hops beyond a certain point show only asterisks, then there may be an outage at that location. Note that some routers are programmed to block IP packets originating from traceroute utilities, so they will always show an asterisk. Traceroute may or may not be able to trace past that point, but this in itself does not indicate a problem.

There is nothing you can do about latency or outages on the various networks comprising the Internet; all you can do is wait for the problem to be resolved by the operator of the network where the problem is located. Traceroute is a good utility to determine exactly where the problem may be occurring.

Public traceroute utilities

It is usually best to take traceroute samples from many points on the Internet, not just from your computer. This will give you a fairly accurate view of where any potential problems may lie.

Traceroute.org is a website that offers links to hundreds of different points of access for the traceroute utility. You can choose to trace from computers in dozens of countries to any other point on the Internet, including your website hosted at Korax.