HyperTerminal and Internet Communication

發行項
10/08/2009

Applies To: Windows Server 2003 with SP1

This section provides information about:

The benefits of HyperTerminal
How HyperTerminal communicates with sites on the Internet
How to control HyperTerminal to prevent the flow of information to and from the Internet

Benefits and Purposes of HyperTerminal

HyperTerminal is a program that you can use to connect to other computers, Telnet sites, bulletin board systems (BBSs), online services, and host computers. HyperTerminal connections are made using a modem, a null modem cable (used to emulate modem communication), or an Ethernet connection.

HyperTerminal has capabilities beyond making connections to other computers. It can, for example, transfer large files from a computer onto your portable computer using a serial port rather than requiring you to set up your portable computer on a network. It can help debug source code from a remote terminal. It can also communicate with many older, character-based computers.

HyperTerminal records the messages passed to and from the computer or service on the other end of your connection. It can therefore serve as a valuable troubleshooting tool when setting up and using your modem. To make sure that your modem is connected properly or to view your modem's settings, you can send commands through HyperTerminal and check the results. HyperTerminal also has scroll functionality that enables you to view received text that has scrolled off the screen.

Note

HyperTerminal is designed to be an easy-to-use tool yet it is not meant to replace other full-featured tools. You can use HyperTerminal as described in this subsection, but you should not attempt to use HyperTerminal for more complex communication. For more information about what HyperTerminal does and does not support, see the Help topics at https://go.microsoft.com/fwlink/?linkid=29890.

Overview: Using HyperTerminal in a Managed Environment

HyperTerminal is not installed by default when a product in the Windows Server 2003 family is installed manually. HyperTerminal is installed by default, however, if the Windows Server 2003 product is installed using an answer file during automated installation. In a managed environment, you might choose to prevent Hyperterminal from being installed on servers running Windows Server 2003. If you choose to allow Hyperterminal to be installed on servers, when deciding how to configure it, consider the following security issues:

Viruses: Incoming files might contain viruses or malicious programs that could compromise or destroy data on your computer. To reduce this risk, use virus-scanning software and ensure that incoming files are from a reliable and trusted source.
ID and password: HyperTerminal cannot automatically provide your login ID and password when you make a connection. If you provide a password when using HyperTerminal for a Telnet session, be aware that this password will be sent to the remote computer using plaintext (as with all Telnet connections).
Automatic download: The automatic download feature of the Zmodem protocol can pose a security risk by allowing remote users to send files to your computer without your explicit permission. To avoid this risk, you should select a protocol other than Zmodem in the Receive File dialog box or you should clear the Allow remote host initiated file transfers check box on the Settings tab of Connection Properties.

Complete information about concepts and procedures associated with using or configuring HyperTerminal is beyond the scope of this white paper. For more information, access the HyperTerminal Help documentation in Help and Support Center on any computer running Windows Server 2003.

How HyperTerminal Communicates with Sites on the Internet

The exchange of information that takes place during the HyperTerminal connection is as follows:

Specific information sent or received: When using HyperTerminal for Telnet connectivity, the user ID and password are sent in plaintext format (as with all Telnet connections). If files are being transmitted, only the protocol, terminal emulation data, and file-specific binaries are sent. The computer running HyperTerminal is identified by its IP address when the connection type is TCP/IP. The computer is not uniquely identified when the connection type is not TCP/IP.
Default settings: HyperTerminal is not installed by default when a product in the Windows Server 2003 family is installed manually. HyperTerminal is installed by default, however, if the Windows Server 2003 product is installed using an answer file during automated installation. To remove or uninstall HyperTerminal, see "Controlling HyperTerminal to Prevent the Flow of Information to and from the Internet," later in this section.
Triggers: When HyperTerminal is set to automatically answer incoming connections, a file transfer can be initiated if the Zmodem transfer protocol is used. Otherwise, communication through HyperTerminal is only triggered when the user deliberately initiates it.
User notification: After a user starts a HyperTerminal connection session, the status of the connection that is currently open within HyperTerminal is displayed in the HyperTerminal title bar. The status of the file and text transfer is displayed in the HyperTerminal window during the transfer process. HyperTerminal does not display connection or transfer status information when the automatic download feature of the Zmodem protocol is used. For more information about the HyperTerminal automatic download feature, see "Overview: Using HyperTerminal in a Managed Environment," earlier in this section.
Encryption: Information sent or received by HyperTerminal is not encrypted.
Transmission protocol and port: The protocols used are Kermit, Xmodem, Xmodem-1K, Ymodem, Ymodem-G, and Zmodem transmissions protocols on port 23.
Ability to disable: You can prevent Hyperterminal from being installed, remove it, or prevent it from being run. For more information, see "Controlling HyperTerminal to Prevent the Flow of Information to and from the Internet," later in this section.

Controlling HyperTerminal to Prevent the Flow of Information to and from the Internet

You can ensure that HyperTerminal cannot be used on a server running Windows Server 2003 by using the following methods, described in the procedures in this section:

For unattended installations, specify an entry in an answer file that will prevent HyperTerminal from being installed.
After installation, use Add or Remove Programs in Control Panel to remove HyperTerminal or to confirm that it is not installed.
Use Group Policy to ensure that HyperTerminal cannot be run.

To Ensure that HyperTerminal is Not Installed During Unattended Installation

Using the methods you prefer for unattended installation or remote installation, create an answer file. For more information about unattended and remote installation, see Appendix A: Resources for Learning About Automated Installation and Deployment.
In the [Components] section of the answer file, include the following entry:

hypertrm = Off

To Remove HyperTerminal from an Individual Computer Running Windows Server 2003

Click Start, and then either point to Control Panel, or point to Settings and then click Control Panel.
Double-click Add or Remove Programs.
Click Add/Remove Windows Components (on the left).
Double-click Accessories and Utilities, and then double-click Communications.
Make sure the check box for the HyperTerminal component is cleared.
Follow the instructions to complete the Windows Components Wizard.

Note

You must have administrative credentials to complete this procedure.

To Use Group Policy to Prevent HyperTerminal from Being Run

As needed, see Appendix B: Resources for Learning About Group Policy, and then edit an appropriate GPO.
In Group Policy, click User Configuration, click Administrative Templates, and then click System.
In the details pane, double-click Don’t run specified Windows applications.
Click Enabled, click Show, click Add, and then type the executable name:

Hypertrm.exe

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