If you do not have telnet on your system, you should be able to download a free copy from the web for any computing platform.
If for any reason you are not connected to the internet, or there is no telnet site at this address, you should get a message indicating that telnet could not open a connection to the specified host (ie the computer at the URL you specified). In this case there is no point in trying this particular connection with a browser, as the browser expects to access a website on a different port. You could, however, use a browser just to check that you are online.
The telnet program by default tries to access the specified server on port 23. You can specify the port to be used when you run telnet, for example like this: telnet HOSTNAME 23. This should work just as before. If you try a different port number then most servers will not respond to the request as they will not be expecting telnet requests on other ports. If you write your own server, of course, you can choose which port it listens to. In this case you could use telnet to communicate with the server on that port, which need not be port 23. We will see how to do this a little later in this unit.
As mentioned previously, the telnet request may not work on some sites, even those suggested here or on the web as offering a telnet service. If it still does not work after trying again a couple of times, you may want to try another site, but don't spend too much time on this. Please make sure you are trying the correct address - there is no www. in the name of telnet sites (as they are not websites). You will write your own server later in the unit that will operate on similar principles.
If you wish to explore further, you may want to try downloading a client supporting ssh, such as "putty" or "mintty"
Note that the Firewall advice you were given in the earlier
activities of this unit, is also
relevant to this activity, because again we are connecting to the
internet.
To enable telnet on Vista or Windows 7 you may need to do the following:
From your Windows Start button, select Control Panel, click Programs and features, and then click Turn Windows features on or off. (Enter a password or provide confirmation if asked to do so.)
In Windows Features tick the check box for Telnet Client.
Click OK and wait for the installation to complete.