108. Network Tools
By Andrew D. Wright
Ever wonder what's going on when a website you're trying to get to doesn't
come up or is very slow?
Your computer has some tools built in that can help. To use those tools
you need to understand a little of how the Internet works.
Everyone has run into a domain before. Hotmail.com, chebucto.ca; these are
domains. A domain is a name and an extension which tells some information
about the domain. The .Ca domain refers to sites for Canadian entities,
for example and also happens to be celebrating its 20th anniversary
Monday, May 14, 2007.
The fact that a website says it is something.Ca does not mean that the
files you are looking at are in Canada though. A domain can be located
physically anywhere in the world.
When you look up a domain, a name server gives you an IP address, a number
that uniquely identifies that one computer. That IP address will have four
sets of numbers separated by periods and each number can run from 0 to
255. For example 220.127.116.11 is the IP address for chebucto.ca.
Once your computer has the IP address of the domain, it sends a request
for information. That is in the form of information packets, little
bundles of data with the IP address they want to go to written on them.
Your computer shoots out a string of these data packets to your internet
provider. The data packets get passed from computer to computer until they
get to the IP address you wanted. In return, it shoots back a string of
data packets answering your request.
So what you see is you type hotmail.com in your web browser and the
Hotmail page comes up. This is when it all works properly.
Open a command prompt in Windows with Start then Run then type in: cmd and
hit Enter. In early versions of Windows open an MS-DOS prompt. In the
command prompt type:
and hit Enter. You should see this:
Pinging chebucto.ca [18.104.22.168] with 32 bytes of data:
Reply from 22.214.171.124: bytes=32 time=11ms TTL=251
This means that you can get the IP address and you can talk to the domain.
No IP address usually means no name server (problem with your provider),
the network settings on your computer are wrong, or you have no internet
Let's say the connection is there but very slow. You can see if this is
coming from network traffic jams and usually even where with the
Traceroute command. In the command prompt type:
and hit Enter. Change machine.name to the website you are trying to get
Traceroute will show all the computers between you and the website you
want and how long it takes to make the hop from one computer to the next.
With traceroute you can see where a connection is broken, slow or timing
out. Some organization firewalls block ping and traceroute data packets so
you may be able to trace a connection only as far as that.
The Mousepad runs every two weeks. It's a service of Chebucto Community
Net, a community-owned Internet provider. If you have a question about
computing, email firstname.lastname@example.org or
click here. If we use your question
in a column, we'll send you a free mousepad.
Originally published 13 May 2007