The most important thing about the TCP/IP (or Transmission Control Protocol/Internet Protocol) is that it enables computers all around the world to communicate with each other, regardless of their operating system.
So, a Windows computer in Washington can talk to a Linux computer in London or a Sun machine in Sydney. And all of this done automatically in the background without any input from the Internet user.
However, this raises an important question for that user. How can they analyse problems when things start to go wrong with the network? Fortunately there are some very simple command line tools to help the Windows user.
Ipconfig
The starting point for any system analysis is, perhaps, ipconfig. If the user calls types "ipconfig" on the command line then they will see the IP set up for their own computer, for example:
And even more information can be obtained by calling ipconfig with it's "/all" flag:
Next the network user can consider whether or not their computer can accually connect to the Internet.
Ping
The ping command sends packets of information to a web server, tests to see if it receives a response, and times how long the response takes:
Ping is particularly useful because of the fact that it confirms that the computer is (or is not) connecting correctly. However, there are other commands that give even more information
Tracert
One interesting command is tracert. This traces the route between the user's computer and any other computer on the network:
Here it can be seen that there are 15 connections between the user's computer and the target host (which is interesting considering that in this case they are only 4 miles apart).
Nslookup
The final command to consider is nslookup. This returns the name and any aliases for a given IP address, for example:
Here the output can be compared with a known IP/name pairing, or it can be used to look up the details for any unnamed hops from the tracert output:
And so, with just these few commands a computer user can query the IP address of their machine, they can check its connectivity to the Internet, they can investigate the route that it's taking in order to make the connection, helping them towards identifying problems with their network.
Mark Alexander Bain - Mark Alexander Bain is a writer, Mo Bro and consultant for all aspects of software development at dsquared. He has also written regularly ...
