Router - Tracing Your Packets

Few people will really care about the path that your packet takes when sending a message, but if you're one of those high tech egg heads then this article may be of great interest to you.  It can become very addictive so proceed with caution. 

If you're using a Microsoft Windows based operation system, then it's very easy to trace the route that your message has taken.  Not only that, you can see exactly how many routers it took to get your message from point A to point B.  You can do this by using a program that is on your computer called Traceroute.  That is exactly what the program does.  It traces the route a message takes to get to its final destination. 

To run the program you have to go to a DOS prompt.  After doing this, go to the C:\windows directory and type tracert followed by the URL of the Internet site you're connected to at the time.  It will give you a rather technical spec sheet of every IP address it stopped at along the way until it got to its final destination. 

The first number on the spec sheet tells you how many routers it went through to get to its final destination.  Then each individual router listed on the page is numbered from 1 down to the last one which is actually the final destination.  The next 3 numbers on each line for each router shows how long the packet took to get to that router.  The next piece of information on each line is the actual name of the router the information went through.  Yes, routers have names.  This may be important to the users but is totally irrelevant to the router itself.  Finally, the last piece of info on each line is the actual IP address of the router itself. 

The amount of time it takes information to get from one router to another varies depending on how much traffic there is on that route at the time.  Normally, it is no more than a couple of seconds.  But occasionally, it can be longer.  That is why sometimes you will be trying to access a web site and it seems to take forever.  This can be for a number of reasons, but usually it is because along the way one of the routers is not working correctly and has to be bypassed.  Sometimes the actual final location itself is down or having problems and the delay is the last router in the chain trying to connect to the network. 

Traceroute is not limited to just checking the number of routers between you and an Internet site.  You can use it to check the number of routers between you and any other computer on a network.  As long as you know the IP address of the other computer you can trace the route of the packets between you and the other computer. 

In our next instalment we're going to look at how routers handle denial of service attacks and other problems.