GoodTech Systems

Telnet is the standard for character-based network communications. It is a part of TCP/IP, the networking protocol of the Internet. Computer users on local area networks and on the Internet use Telnet to connect to a remote host and execute programs on the host.

What is Telnet Server?

Telnet server allows remote users to Telnet in to a host.

What is Telnet Client?

Telnet client allows a user to Telnet out to run a program on remote hosts.

Does Microsoft Windows NT has built-in Telnet Server and Telnet Client?

Microsoft Windows NT networking has a built-in Telnet client, but does not have a built-in Telnet server.

What is GoodTech Telnet Server?

Goodtech Telnet Server provides Telnet Server functionality. When Goodtech Telnet Server is installed on your Windows NT system, you can Telnet from remote systems and run programs on your Windows NT system.

Why do users want to Telnet in to a system?

To remotely administer a system

To administer a system, you must be at the console of that system. With telnet, the remote administrator can support a system that may be physically located miles away.

To support old Dos applications

Telnet allows moving applications from old platforms to run on NT. Telnet is used to provide the interface to the users.

To run multiple users on a single Windows NT system

Windows NT can handle multiple users running different jobs at the same time, but only one user can be using the system console at a time. Telnet allows multiple users to be concurrently logged in.

To run programs where they run most efficiently

Telnet allows remote users to run programs on the host rather than on their machine. It is more efficient to do so in case the program requires large amounts of data that reside on the host.

What programs are supported by telnet?

Telnet does not support graphical programs that use Windows. Telnet runs any program that runs in your Windows NT DOS Window.

HOW DOES GOODTECH TELNET SERVER NT WORK?

What does the installation program do?

The installation program creates a telnet service called telnetd and adds it to the list of services available on your NT system.

What does the telnet service do?

When the Telnet Server service is started, either manually or automatically, it runs a program named telnetd.exe.

The program telnetd.exe opens a log file telnetd.log in the %systemroot%\system32 directory.

Telnetd.exe is now ready for connection requests. It listens to requests on the default telnet port (#23) or on other port if a different port was specified when the telnet service was started.

What happens when a remote user tries to connect?

When a user wants to telnet out to the host running GoodTech telnet server, he runs a telnet client program. The telnet client sends a connection request to port #23 (or to any other port the telnet server was configured to listen).

The telnetd.exe program gets the request and opens a thread, which is responsible for this connection. This thread relieves telnetd.exe from communicating with the client and let it focus on listening to other connection requests.

The client thread starts the authentication process. It asks the telnet client for login information. The login information consists of a User ID, Password and optional Domain. The client thread then uses the internal NT security mechanism to check if the user is allowed to the host.

If the user passes authentication, he is logged onto the host system.

The client thread creates a process that runs a program named telcmd.exe. The telcmd.exe program creates a shell process that by default runs the cmd.exe. The remote user is now ready to work on the host.

EVALUATION COPY

What are the limitations of the evaluation copy?

The free evaluation copy of the Telnet Server will expire 30 days from when it is installed. It is also limited to two connections.

INSTALLATION

How do I install the GoodTech Telnet Server?

After downloading/receiving the Telnet Server:

Unzip the Telnetd zip file to your installation directory.
Run install.exe to install GoodTech Telnet server. The installation creates a new service with the internal name TELNETD.
Start GoodTech Telnet server service.

I fail to run the install.exe program.

If you get an error number 1073 (service already exists), it means that a service with a name telnetd (the internal name of GoodTech Telnet Server service) is already in use in your system. You have to uninstall the existing service before you install GoodTech Telnet server.

I want to install a new version of the Telnet Server but have a previous version currently on my system.

1. Stop the GoodTech Telnet Server Service.

2. Run uninstall.exe to uninstall your current version of GoodTech Telnet server.

3. Follow the installation steps for the new version.

How do I specify an automatic startup for the GoodTech Telnet Server?

Go to the Control Panel / Services program, select GoodTech Telnet Server from the list of Services, push the Startup button, and then, select automatic startup.
The next time you will restart your computer, the GoodTech Telnet Server service will start automatically.

Port #23 is occupied (the default port for telnet server). Can I use another port?

You can use another port by giving a number other than 23 in the Startup parameters input box when starting the Telnet Server service.(if no number is specified, port 23 is used.)

The screen shot below is an example of using port 25 when starting the Telnet Server.

How do I refer to a logon script that is located in a directory other than the default directory?

In order to use logon scripting you should put the logon scripts usually in directory:
C:\systemroot\SYSTEM32\REPL\IMPORT\SCRIPTS (The default path).
If the logon script is located in a subdirectory of the default logon path, precede the filename with that relative path. For example, you might type clerks.bat or you might type \admin\clerks.bat, if the file is located in a subdirectory admin under the default logon path.

SERVICE MANAGEMENT

How do I start GoodTech Telnet Server Service?

You have a few options:

Go to the Control Panel / Services program, select GoodTech Telnet Server from the list of Services and press the Start button.

Go to a DOS Prompt and type "NET START TELNETD"

Is it possible to remotely restart the Telnet Server?

Yes.You have to do the following:

Create a bat file (i.e. remoterestart.bat) with the following lines in it-

net stop telnetd

net start telnetd

Logon to the server from a remote telnet session as a privileged user and execute the bat file-

start /b <bat file> for example: start /b remoterestart

The remote session will be disconnected, but you can reconnect.

To check your user has the right privileges-

logon locally as this user (not in a telnet session)

run the bat file and make sure you get no errors.

How do I stop the GoodTech Telnet Server Service?

You have a few options:

Go to the Control Panel / Services program, select GoodTech Telnet Server from the list of Services and press the Stop button.

Go to a DOS Prompt and type "NET STOP TELNETD"

You can also use the monitoring command "telnetd shutdown".

How do I pause the GoodTech Telnet Server Service?

You have a few options:

Go to the Control Panel / Services program, select GoodTech Telnet Server from the list of Services and press the Pause button.

Go to a DOS Prompt and type "NET PAUSE TELNETD"

You can also use the monitoring command "telnetd disable".

How do I continue the paused GoodTech Telnet Server Service?

You have a few options:

Go to the Control Panel / Services program, select GoodTech Telnet Server from the list of Services and press the Continue button.

Go to a DOS Prompt and type "NET CONTINUE TELNETD"

You can also use the monitoring command "telnetd enable".

MONITORING COMMANDS

What monitoring commands are available?

"telnetd status": Shows all user connections

"telnetd kill <sid>": Kills a client session identified by <sid>

"telnetd disable": Disables new connections to host machine

"telnetd enable": Enables connections to host machines

"telnetd shutdown": Shutdowns the GoodTech Telnet Server Service

How do I use the monitoring commands?

You should log on to the host machine as telnetd user, either locally or from a remote machine.
Type the command At the command shell prompt of the Telnet client. Make sure that you are not located in the Telnet Server installation directory (where the program telnetd.exe resides).

The screen shot below shows as an example the command "telnetd status".

I can not get the monitoring commands to work.

Don't confuse the program telnetd.exe with the telnetd monitoring commands. The telnetd monitoring commands can be executed as described under the question " How do I use the monitoring commands". A common mistake is to run the telnetd.exe with "parameters", such as status.

WORKING WITH THE TELNET SERVER

How do I establish a new connection to the host machine?

You have to use a telnet client to log on to the host machine. GoodTech Telnet server supports all standard telnet clients that are currently available in the market.

The screen shot below uses Microsoft Telnet client that comes with Windows NT.

I fail to log on to the host machine.

Check the user privileges. Users must have "log on locally" access permission in order to log on locally to the server (host) machine. To grant privileges to user, use the User Manager program.

What should I enter at the domain prompt in the login process?

You have two options:

1. For remote authentication - give a domain name

2. For local authentication (on the server where the Telnet Server is running) - leave it blank

I'd like to make use of either 4Dos for WindowsNT(4NT) from JP Software or the bash shell. I'd like to know whether your software supports a command interpreter other than CMD.EXE, and if so, what do I need to do to enable the alternate command interpreters?

You can use 4NT shell instead of CMD shell. You have two ways to do it:

Use the default CMD shell and then use 4NT shell by running the 4NT.exe program from the Telnet session.

Change your ComSpec system variable to point to the 4NT.EXE program instead of to CMD.EXE program. You can change that from the System icon, then restart the computer for the change to take effect.

We only support user logon script when the authentication is made in the local machine where the Telnet Server is running.

Is there a limit to the number of connections supported by the Telnet Server?

The number of connections you purchase limits the maximum number of concurrent connections. The maximum concurrent connections you can purchase are 255 (but it is actually unlimited).

PowerTerm does not communicate well the window size with the Telnet Server. You can try CRT Telnet client from Vandyke (http://www.vandyke.com).

TELNET CLIENT PRODUCTS

What telnet client can work with GoodTech telnet server?

GoodTech Telent Server is written in open standards and can work with any standard telnet client. There are quite a few telnet clients available, many of which are free. However, CRT from Van Dyke Technologies is our preferred telnet client because it is flexible and friendly and it is less likely to run into problems when using it with GoodTech Telnet Server because GoodTech Telnet Server is thoroughly tested with CRT.

The Windows 95,98/NT operating systems are shipped with a telnet client included (found at "c:\windows\telnet.exe" and "c:\winnt\system32\telnet.exe" respectively). This telnet client is simple and functional, but not quite as flexible and friendly as CRT from Van Dyke Technologies, Inc. or POWER TERM from Ericon Software, which have to be purchased.