In Windows Vista, both Telnet client and Telnet server features are available, although they are not turned on by default. Instead, these features can be turned on by an administrator (or a user with an administrator account).
If you are running a small workgroup of computers, you may want to use a computer running Windows Vista as a Web server for ASP.NET development. You can do so by installing Internet Information Services (IIS).By default, IIS 7.0 is not installed on Windows Vista® Business or Windows Vista® Ultimate.It provides for basic Web server functionality and includes the WWW, FTP, NNTP, and SMTP services.If you want to install IIS server you need to have vista business or ultimate editions.
You can enable telnet client and server using the following steps
Click Start—>Click Control Panel
Now Click Programs
Click Programs and Features
Select Windows features on or off from the left column
In the Windows Features dialog box, click Telnet client,Telnet Server and then click OK.
To prevent users from turning on the Telnet client or Telnet server, you can ensure that they do not have administrator accounts. As an additional step, you can use a script to check if Telnet.exe is present on a computer that runs Windows Vista.
Note:-A terminal-emulation program called Hyperterminal was available in Windows XP, but it is not available in Windows Vista.