Using Telnet

Applies To: Windows 7, Windows 8, Windows Server 2008, Windows Server 2008 R2, Windows Server 2012, Windows Vista

Using Telnet involves three basic steps:

1. Start the Telnet server program on the host

2. Connect to the Telnet server from the Telnet client

3. Run programs in the Telnet session

Start the Telnet server program on the host

On Windows, Telnet Server (Tlntsvr.exe) runs as a service. You can start the service manually every time you want to allow Telnet connections your computer, or you can configure the service so that it starts every time your computer starts. Telnet clients cannot connect to a host unless the Telnet Server service is running and listening for connection requests. For more information about configuring the Telnet Server service, see Managing Telnet Server.

Connect to the Telnet server from the Telnet client

To create a Telnet connection between a Telnet client and a Telnet server, start the Telnet Client service on the client. When you run Telnet Client (Telnet.exe), you must specify the host to which you want to connect. You can also configure several optional connection settings and features. For more information about how to use the Telnet Client service on Windows, see Managing Telnet Client.

When you run the Telnet Client service, it makes a connection request to the Telnet server. If a Telnet server responds to the request, the Telnet client and server negotiate the details of the connection, such as flow control settings, window size, authentication types supported, and terminal type to be emulated. After the connection details are successfully negotiated, and logon credentials are validated, the Telnet Server service creates a Telnet command prompt session.

On Windows, each Telnet command prompt session consists of two processes: TlntSess.exe and Cmd.exe. TlntSess.exe is responsible for managing the Telnet session. Cmd.exe is the command interpreter, or shell program, that runs commands, programs, or scripts on the host.

Run programs in the Telnet session

After you establish a Telnet connection between the Telnet client and the Telnet server, the following message appears in the command prompt window on the client:

Welcome to Microsoft Telnet Server.

This message indicates that you have established a session to an active Telnet server. Depending on how the server is configured to authenticate its users, you might be asked for a user name and password. After you successfully complete authentication, and you can use this session to remotely run command-line programs, shell commands, and scripts on a Telnet server. The programs you can run depend upon the permissions granted to your user account, or the user groups of which your account is a member. If User Account Control is enabled on your computer, it can impact what programs you can use during the Telnet session.

Telnet client and server processes rely on the Telnet network virtual terminal (NVT) to translate operating system-specific keyboard and display codes to Telnet character codes that all Telnet clients and servers can understand. For more information, see Configure the Telnet Terminal Type.

See Also

Concepts

Introduction to Administering Telnet
Best Practices for Administering Telnet
Understanding Telnet
Installing Telnet
Managing Telnet Client
Managing Telnet Server
Telnet Additional Resources