What is telnet. TELNET—Basics of Use

Not all computer users are aware of the presence of hidden services that allow you to perform various operations without using special software. In operating rooms Windows systems and Linux there is a Telnet service. This material will discuss in detail the purpose of the service, commands, capabilities and how to work with it correctly.

What is Telnet

Telnet is a means of communication that is established between terminal devices. An example of such a connection is quite simple: a personal computer and a server that supports a similar type of connection. Telnet is not any software, it is communication protocol. But it should be noted that there are some utilities that work via the “terminalnetwork” protocol.

In the recent past, Telnet was one of the main ways to connect to the network. Now the utility practically not used. Today, operating systems have more advanced protocols installed, eliminating any additional actions from the user.

This communication protocol is used in some operations:

• connection to a remote desktop;
• examination ports for connectivity;
• usage software that is only available on remote machines;
• application system directories, which can only be opened using this type of protocol;
• sending email without using additional software;
• users using this protocol allows other users gain access to your personal computer.

Installation and launch

There is no need to download the utility; Telnet is built into Windows 7/8/10 by default.

Installation and startup instructions:

In order to start the client you need to open the command line:

We invite you to watch the video on installing Telnet in Windows:

Port check

Examination network port for access to a personal computer via Telnet:

• in the window you need to enter the telnetip command;
• what follows enterIP address computer, for example, 192.168.1.1. You can view the address in the settings of your network router;
• At the end, enter the FTP port “21”. Thus the command will look like this: telnet 192.168.0.1 21;
• after that it will appear error message if the port is unavailable or asking you to enter additional data if the port is open.

Telnet Commands

Utility commands are a way to interact with it. To display list of all commands, you must enter “help”. Next, we will look at the main commands in detail:

• “open” - the request allows connect to a remote server;
• "close" - process interruption connecting to a remote server;
• "set" - setting server connection parameters;
• "term" - the request is intended for terminal type indications;
• "escape" - sets control character;
• "mode" - choice operating mode;
• "unset" - reset previously entered parameters;
• "start" - launch servers;
• "pause" - temporary stop server operation;
• "continue" - continuation of work servers after a pause;
• "stop" - complete work stoppage server.

Telnet on Linux

Like Windows, Telnet is built into the operating system. Linux system. Previously it was used as the standard Telnet protocol, now it has been replaced by the more improved SSH. As with the previous OS, the utility in Linux is used to check ports, routers, etc.

Let's look at the main operating modes:

• « line by line». This mode work is recommended. In this case, editing the request is carried out on the local PC and is sent to the server only when it is ready;
• « character-by-character" Every character typed in the console window is sent to the remote server. You cannot edit the text here. When you delete a character using “Backspace”, it will also be sent to the server.

Basic commands in Linux:

• “close” — interrupt the connection;
• “encrypt” — enable encryption;
• “logout”—turn off the utility and close the connection;
• “mode” — selection of operating mode;
• “status” — connection status;
• “send” — sending a telnet request;
• “set” — setting server parameters;
• “open” — connection to a remote server;
• "display" - display special characters.

• in the console window enter a request for server availability checks, for example, "telnet 192.168.1.243";
• Next, let’s check access to the port by entering the request “telnet localhost 122” and “telnet localhost 21”. A message will appear on the console screen indicating whether any of the ports are accepting the connection;
• example of remote control using telnet. To do this, enter the request “telnet localhost 23” in the main window. "23" is the default port. To perform remote control, you need to install “telnet-server” on your local computer. After this, a message will appear asking you to enter your login and password.

Disadvantages of Telnet

The main disadvantage of this protocol is the remote connection without using encryption. The only security point is the authorization of users in the telnet session. But nevertheless, the login and password are also transmitted in unencrypted form, so access to them can be obtained one way or another. It is strongly recommended not to transmit any important data over local networks.

Telnet is not an internal or external command

This error appears if this client not installed on personal computer. You need to do the following:

Second way:

Telnet- This network utility, which allows you to connect to the remote port of any computer and install interactive channel communication, for example, to send commands or receive information. We can say that this is a universal browser in the terminal that can work with many network protocols.

This utility was very often used to remotely control a Linux computer, but then it was replaced by the secure SSH protocol. But telnet is still used, for example, for network testing, port checking, and also for communicating with various IoT devices and routers. In this article we will look at what telnet is, as well as how to use telnet to solve your problems.

What is Telnet?

As I said, this utility is designed to create an interactive connection between remote computers. It works using the TELNET protocol, but this protocol is supported by many services, so it can be used to manage them. The protocol is based on TCP, and allows you to send regular string commands to another device. It can be used not only for manual control but also for interaction between processes.

To work with this protocol we will use the telnet utility, it is very easy to use. Let's look at the telnet syntax:

$ telnet options host port

The host is the domain of the remote computer to connect to, and the port is the port on that computer. Now let's look at the main options:

• -4 – force the use of ipv4 addresses;
• -6 – force the use of ipv6 addresses;
• -8 – use 8-bit encoding, for example, Unicode;
• -E– disable support for Escape sequences;
• -a– automatic login, takes the username from the USER environment variable;
• -b– use a local socket;
• -d– enable debugging mode;
• -r– rlogin emulation mode;
• -e– set the beginning character of the Escape sequence;
• -l– user for authorization on the remote machine.

That's all there is to it telnet commands to establish a connection. But connecting to a remote host is only half the battle. After installation telnet connections can work in two modes:

• Line by line– this is the preferred mode, here a line of text is edited to local computer and is sent only when it is completely ready. Not all services always have this option;
• Character-by-character– all characters you type are sent to a remote server. It will be difficult to correct anything here if you make a mistake, because Backspace will also be sent as a symbol and a movement arrow too.

The use of telnet is to send special commands. Each service has its own commands, but the protocol has its own telnet commands that can be used in the telnet console.

• CLOSE– close the connection to the server;
• ENCRYPT– encrypt all transmitted data;
• LOGOUT– exit and close the connection;
• MODE– switch the mode, from lowercase to character or from character to lowercase;
• STATUS– view connection status;
• SEND– send one of the telnet special characters;
• SET– set the parameter value;
• OPEN– establish a connection via telnet with a remote host;
• DISPLAY– display the special characters used;
• SLC– change the special characters used.

We will not consider all the commands, since you are unlikely to need them, and if you do, you can easily find them in the official documentation.

How to use telnet?

Next we will look at how to use telnet to solve your problems. Usually, the utility is already installed on most systems, but if this is not the case, then you can install telnet from the official repositories, for example, in Ubuntu:

$ sudo apt install telnet

You don't have to use telnet for this; ping is available.

2. Port check

Using telnet we can check the availability of a port on a host, and this can already be very useful. To check the telnet port run:

$telnet localhost 123 $telnet localhost 22

In the first case, we see that no one accepts the connection, but in the second, a message about a successful connection and a greeting from the SSH server are displayed.

3. Debugging

To enable debug mode and output more detailed information while running, use the -d option while connecting:

$ sudo telnet -d localhost 22

4. Telnet console

Using the telnet console is also an important point in understanding how to use telnet. In the main mode, you can execute commands on a remote server, but if you want to address the command specifically to telnet, for example, to configure its operation, you need to use a special character to open the console, usually the utility immediately tells you what this character is, for example, it is used by default “^[“:

To activate it, you need to press the key combination Ctrl+[, then you will enter the telnet input prompt.

To see all available commands, you can type ?. For example, you can view the connection status:

telnet>status

There are other interesting possibilities here. Such things can be done on any connection using the telnet utility.

5. View the telnet site

One common way to use telnet is to test a website from the console. Yes, you won’t get a beautiful web page, but you can manually collect requests and see all the data sent by the server.

$ telnet opennet.ru 80

Then issue the command to the web server.

Protocol application level TELNET (from English. T.E. rmina LNET work) - network protocol to implement a text interface over the network. Name telnet We also received client programs for implementing this protocol for almost all existing operating systems. The Telnet protocol is one of the oldest network protocols, developed as a means of communication between remote terminals in test mode. Therefore, it does not provide data encryption and the use modern means authentication. The protocol is vulnerable to many network attacks, and cannot be used as a tool to manage network operating systems. Currently, for remote access The system uses the SSH (Secure SHell) network protocol, the creation of which focused specifically on security issues. The relative security of Telnet sessions occurs only in a fully controlled network environment or with security applied network level(various implementations of VPN - virtual private networks). However, TELNET is still used to manage specialized network devices (Switches, routers, etc.), as well as for network diagnostics, debugging and studying other text-oriented (telnet-like) protocols based on the TCP transport. The current Telnet protocol standard is described in RFC 854.

In modern OS Windows family, utility telnet.exe by default, not installed. To install it you need to go to Control Panel - Programs and Features - Turn it on or off Windows components and check the box for Telnet client. Or in command line running as administrator, run the command:

pkgmgr /iu:"TelnetClient"

Command line format:

telnet [-a][-e Symbol][-f File][-l Name][-t Type][Host [Port]]

Command line options:

-l The user name to log into the remote system, assuming the TELNET ENVIRON option is supported.

-a Attempt automatic login into the system. Like the -l switch, but uses the current username under which you are logged in.

-e Service character for switching input mode in the telnet client window.

-f Client-side log file name. In the Russian help, this parameter is incorrectly interpreted as Login_File - “File name on the client side for logging into the system.”

-t Telnet terminal type. 4 types of terminals are supported: vt100, vt52, ansi and vtnt.

Knot The host name or IP address of the remote computer to which you are connecting. Port Port number or service name. If the number is not specified, then it is used standard port Telnet 23\TCP

When launched without parameters, the utility goes into command input mode:

Welcome to the Microsoft Telnet Client

Microsoft Telnet>

When entering a character ? or help Help information is displayed:

Teams may be shortened. Supported commands are:

c-close- close the current connection

d-display- display operation parameters

o - open hostname [Port]- connect to the site (by default, Port = 23)

q - quit- exit telnet

set-set- set parameters ("set?" to display a list of them)

sen - send- send strings to the server

st - status- display information about the current state

u - unset- reset parameters ("unset ?" to display a list of them)

? /h - help- issue a certificate

Some of the commands allow you to get hints for use when entered with a question character:

Telnet> set ?- get a hint on using the mode setting command. Example of information displayed:

bsasdel- symbol BackSpace Delete

crlf- carriage return mode; causes CR & LF characters to be sent

delasbs- symbol Delete will be sent as a character BackSpace

escape x- where x is the symbol for switching to telnet terminal mode and back

localecho- enable local echo.

logfile x- where x is the log file. In Russian translation it is incorrectly interpreted as “Current client login file”

logging- recording the current session in the log. In Russian translation it is incorrectly interpreted as "executing a login"

mode x- where x=console is the console mode used to work with windowed applications (vi editor) and x=stream is the streaming mode used to work on the command line.

ntlm- enable NTLM authentication.

term x- type of emulated terminal. Where x is ansi, vt100, vt52, or vtnt.

For tips on canceling set parameters the command is used

Microsoft Telnet> unset?

bsasdel- symbol BackSpace will be sent as a character Delete

crlf- line feed mode; causes the CR character to be sent

delasbs- symbol Delete will be sent as a character Backspace

escape- the symbol for switching to telnet terminal mode and back is not set

localecho- disable local echo

logging- disable log recording. In the Russian-language version it is incorrectly interpreted as "disabling login"

ntlm- disable NTLM authentication.

Examples of commands in interactive mode:

open 192.168.0.1- connect to the Telnet server with an IP address 192.168.0.1

o zte-f660- connect to a Telnet server named zte-f660. Command abbreviation used o pen

set logfile C:\telnet.log- use as log file C:\telnet.log

set logging- record the current session to a log file.

display- display the parameters of the current session. Example of information displayed:

Mode switch symbol: "CTRL+]"

NTLM Authentication - Enabled

Local echo output - disabled

Mode new line- Symbol ENTER will be shipped as CR & LF

Current mode: Streaming

TERMINAL MODE

Preferred ANSI Terminal Type

    In practice, the utility telnet.exe used as a diagnostic and debugging tool to connect not only to the Telnet server on TCP port 23, but also to any other TCP port, thereby allowing you to interact with any command line-controlled application. So, for example, using the utility telnet you can connect to servers that support text (telnet-like) input of commands and data - SMTP, POP3, IMAP, etc. In addition, the utility can be used as a means of roughly checking the connectivity to any TCP port (checking whether a specific TCP port is listening).

telnet 192.168.1.1 8080- connect to host 192.168.1.1 on port 8080. In cases where the port is closed, the utility will report that connection is impossible. Moreover, to check the availability of a certain port, it is not even necessary that it be listened to by a service that supports text input, such as a VNC server. To disconnect from the remote server, you must enter the mode switching symbol (by default - CTRL+]).

The telnet.exe utility can be used, for example, to communicate with mail server according to the protocol POP3(Post Office Protocol ver. 3). This protocol used by email clients (Outlook, Outlook Express, The Bat, etc.) to receive email stored in mailbox user. This is the simplest protocol based on the exchange text messages. In order to study the interaction mail client with a mail server, you can implement a connection session using TELNET.

By default, the POP3 server listens for incoming connections via TCP protocol to port 110 ("listens" to port tcp/110). Telnet command to connect to a server, for example pop.mail.ru

telnet pop.mail.ru 110

If the server is healthy, its invitation will appear in the telnet window

+OK mPOP POP3 v1.1

user [email protected]

After which, the server will prompt you to enter a password:

OK Password required for user [email protected]

You need to enter a password

pass VasinPass

The server will report the result of the password check:

You can request a list of letters with a directive list:

list

In response to this, the server will display a list and sizes of letters in the mailbox:

OK 10 messages (152527 octets)
1 48628       1 is the serial number, 48628 is the size
2 1829
3 2070
:

If necessary, you can view the headers of the letters. To do this, use the command top sequence number, space, number of lines from the message body

top 2 0

In response to this, you will see the header of the letter containing service information about the sender, date of sending, return address and some other data:

Received: from (HELO mx1.ks.pochta.ru) by node7-1.ks.pochta.ru with QIP.RU LMTP
for [email protected];
Fri, 08 Apr 2011 15:18:33 +0400
Received: from mx3.softkey.ru ()
: :

The directive is used to receive letters retr sequence number

retr 2 - receive a letter with sequence number 2

To delete a letter, use the directive dele sequence number For example, to remove the 2nd letter from the list received by the directive list:

If the deletion was successful, the server will display the following message:

OK message 2 deleted

Sometimes, the TELNET command can also be used to identify the service listening on the specified port, since many of them display either their banner or specific service information when connected. For example, the FTP server greeting: 220-FileZilla Server version 0.9.43 beta

220-written by Tim Kosse ( [email protected])

220 Please visit http://sourceforge.net/projects/filezilla/

And this is what the screen looks like when connecting to the RealVNC server:

RFB 003.008

With the advent of computers and networks, corresponding programs also appeared for remote control of the system and for transmitting data over a distance. First of all, something like this software put inside operating system still in a standard form, which significantly alleviates the problem - no search for software for remote control is required. In order to connect to a specific computer from a distance, you can use a regular Windows console terminal, called the command line or otherwise known as cmd.

To contact a specific computer on the network remotely, you just have to take full advantage of the remote control The system has a "telnet" command. This command will provide not only the extraction of information, but also control of all actions occurring in this system.

The "telnet" command is present on all Windows versions. But not on all versions Windows given the command is configured as required. For example, to use “telnet” on Windows 7, you need to make a number of simple settings to connect this module.

All that is required for the "telnet" command to be available is the presence of a network, as well as the system user's membership in the Administrators group. All settings are made through the menu items "services.msc". This service can be launched via search. When you launch it, you need to click on the “telnet” sign with the right mouse button and then select properties. In properties you can make a wide variety of settings for of this connection, as well as change the startup type of this service. "Telnet" for Windows 7 contains three launch options: manual mode, automatic mode and shutdown mode.

If you access remote control using the input line, the "telnet" command has a number of other additional commands, thanks to which the user determines which computer on the network will be connected to, through which port, and the user can also enter the full path to any file or view the entire directory using a regular command.

In order to take advantage of all the promising conditions of “telnet”, before connecting to it, you should make sure that the Firewall settings are correct, since any incorrectness in terms of settings can entail a lot of other consequences. Incorrect configuration, in turn, will not make it possible to implement

Another reason why the connection may fail is errors. They can be issued in connection with any failure in the system or due to incorrect settings. The reason for the lack of connection can be determined by the error code, since each of the errors issued will contain its own number, which, in turn, will help identify the malfunction and eliminate it. If this server is intended for constant use, then it is better to configure it every time you start the computer. Similarly, you can configure the server to start manually.

Teams telnet allow you to contact remote computer using the Telnet protocol. You can run the command telnet without parameters to enter the telnet context indicated on the Telnet command line ( telnet). From the Telnet command line, use the following commands to control the computer running the Telnet client.

Teams tlntadmn allow you to remotely control a computer running a Telnet server. These commands are executed from the command line. Team tlntadmn without parameters displays the local server setting.

To use commands telnet from the Telnet command line

To launch the Telnet client and enter the Telnet command line

Syntax

telnet [\\ remote_server]

Options \\ remote_server Displays the name of the connected server /?

• When using the command telnet The Telnet client starts without parameters.
• At the Telnet command line, you must use Telnet commands.

To stop the Telnet client

Syntax

Options

none

Notes

• This command can be shortened to q.

To connect a Telnet client to a remote computer

Syntax

open [\\ remote_server] [port]

Options \\ remote_server port Indicates the port to use. If no port is specified, the default port is used. Notes

• This command can be shortened to o.

To connect to the remote Redmond server on port 44, enter at the command prompt: redmond 44

To disconnect the Telnet client from a remote computer

Syntax

close [\\ remote_server]

Options \\ remote_server Specifies the name of the managed server. If the server is not specified, it is used local server. Notes

• This command can be shortened to c.

To disconnect from the remote Redmond server, enter the command: c redmond 44

To configure settings Telnet client

Syntax

set [\\ remote_server] [ntlm] [localecho] [term {ansi | vt100 | vt52 | vtnt}] [escape symbol] [logfile file name] [logging] [bsasdel] [crlf] [delasbs] [mode {console | stream}] [? ]

Options \\ remote_server Specifies the name of the managed server. If no server is specified, the local server is used. ntlm Enables NTML authentication if available on the remote server. localecho Enables local command display mode. term {ansi | vt100 | vt52 | vtnt) Specifies a terminal of the specified type. escape symbol Specifies the control character. The control character can be a single character or a combination of the CTRL key and a character. To set a key combination, hold down the CTRL key while typing the character you want to assign. logfilefile name Specifies the Telnet activity log file. The log file must be located on your local computer. Logging starts automatically after selecting this option. logging Enables logging. If a log file is not specified, an error message is displayed. bsasdel Specifies the BACKSPACE key to delete. crlf Assigns a new linear mode, which defines the ENTER key as 0x0D, 0x0A. delasbs Assigns the DELETE key to delete the last character. mode {console | stream) Sets the operating mode. ? Allows you to view the full command syntax. Notes

• To disable a previously assigned setting, at the Telnet command prompt, enter:

  unset [parameter]

• To assign a control character, enter the command:

  -e symbol

• In non-English versions of Telnet, the command is available codeset parameter. Codeset parameter specifies the current code set for the parameter, which can be one of the following: Shift JIS, Japanese EUC, JIS Kanji, JIS Kanji (78), DEC Kanji, NEC Kanji. You must assign the same code set on the remote computer.

To send Telnet client commands

Syntax

send [\\ remote_server] [ao] [ayt] [esc] [ip] [synch] [? ]

Options \\ remote_server The name of the server that you want to manage. If no server is specified, the local server is used. ao Cancels an input command. ayt Sends the command "Are you there?" esc Sends the current control character. ip Aborts execution of a processing command. synch Performs a Telnet synchronization operation. ? Allows you to view the full command syntax.

To view the current Telnet client settings

Syntax display

Options

None

Notes

• This command displays the current operating parameters for the Telnet client. When operating in Telnet session mode (in other words, while connected to a Telnet server), you can exit the session to change settings by pressing CTRL+]. To return to the Telnet session, press ENTER.

To use commands tlntadmn from the command line

To administer a computer running Telnet server/P>Syntax

tlntadmn [\\ remote_server] [start] [stop] [pause] [continue]Options \\ remote_server Specifies the name of the server that you want to take control of. If no server is specified, the local server is used. start Starts the Telnet server. stop Stops the Telnet server. pause Terminates the Telnet server. continue Restarts the Telnet server. /?

• Using commands tlntadmn tlntadmn

To administer Telnet sessions

Syntax

tlntadmn [\\ remote_server] [-s] [-k{session_code | all}] [-m {session_code |all} " message" ]

Options \\ remote_server -s Displays active Telnet sessions. -k{session_code | all) Ends sessions. Enter a session code to end a specific session or enter all to end all sessions. -m {session_code | all} " message" Sends a message to one or more sessions. Enter a session code to send a message to a specific session, or enter all to send a message to all sessions. Type the message you want to send in quotes (i.e. " message" ). /? Displays help on the command line. Notes

• Using commands tlntadmn you can remotely administer a computer running a Telnet server if both computers are running Windows control XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.

To set event log settings for the computer running Telnet Server

Syntax

tlntadmn [\\ remote_computer] config [auditlocation={eventlog | file | both}][audit=[{+ | - } admin][{+ | - } user][{+ | - } fail]]

Options \\ remote_server auditlocation={eventlog | file | both) Specifies whether event information should be sent to the Event Viewer, to a file, or to both. audit=[{+ | - } admin][{+ | - } user][{+ | - } fail] Specifies which events require auditing (administrator logon events, user logon events, or failed logon attempts). To audit a specific event type, enter a plus sign (+) in front of the event type. To stop auditing of a specific event type, enter a minus sign (-) in front of the event type. /?

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.
• If you specify where to send event information without specifying the information type or types to be audited, only administrator log event information will be audited and sent to the specified location.

To send event information to the Event Viewer, enter:

tlntadmn config auditlocation=eventlog

To audit administrator logon events and failed logon attempts, enter:

tlntadmn config audit=+admin +fail

To set the primary domain for the computer running Telnet Server

Syntax

tlntadmn [\\ remote_server] config [dom=domain_name]Options \\ remote_server Specifies the name of the server that you want to take control of. If no server is specified, the local server is used. dom=domain_name Specifies the domain that you want to make primary. /? Displays help on the command line. Notes

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.

To make the Redmond domain the primary domain on your local server, enter:

tlntadmn config dom=Redmond

To map the ALT key to the computer running the Telnet server

Syntax

tlntadmn [\\ remote_server] config [ctrlakeymap={yes | no}]

Options \\ remote_server Specifies the name of the server that you want to take control of. If no server is specified, the local server is used. ctrlakeymap={yes | no) Indicates whether the Telnet server should interpret the CTRL+A key combination as ALT. Enter yes to map a keyboard shortcut or no to refuse matching. /? Displays help on the command line. Notes

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.
• If ALT key is not mapped, the Telnet server does not send the ALT keystroke to applications where it might be required.

To set the maximum number of connections for the computer running Telnet Server

Syntax

tlntadmn [\\ remote_server] config [maxconn=positive_integer]

Options \\ remote_server Specifies the name of the server that you want to take control of. If no server is specified, the local server is used. maxconn=positive_integer Sets the maximum number of connections. This number can be specified using any positive integer less than 10 million. /? Displays help on the command line. Notes

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.

To set the maximum number of failed access attempts for the computer running the Telnet server

Syntax

tlntadmn [\\ remote_computer] config [maxfail=positive_integer]

Options \\ remote_server Specifies the name of the server that you want to take control of. If no server is specified, the local server is used. maxfail= positive_integer Sets the maximum number of failed login attempts allowed for a user. This number can be specified using any positive integer less than 100. /? Displays help on the command line. Notes

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.

To set the operating mode for the computer running the Telnet server

Syntax

tlntadmn [\\ remote_server] config [mode={console | stream}]

Options \\ remote_server mode {console | stream) Indicates the operating mode. /? Displays help on the command line. Notes

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.

To set the Telnet port for the computer running the Telnet server

Syntax

tlntadmn [\\ remote_server] config [port=integer_value]

Options \\ remote_server Specifies the name of the server that you want to take control of. If no server is specified, the local server is used. port=integer_value Specifies the Telnet port. The port can be specified using any integer less than 1024. /? Displays help on the command line. Notes

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.

To set authentication methods for the computer running the Telnet server

Syntax

tlntadmn [\\ remote_server] config [sec=[{+ | - } ntlm][{+ | - } passwd]]Options \\ remote_server Specifies the name of the server that you want to take control of. If no server is specified, the local server is used. sec=[{+ | - } ntlm][{+ | - } passwd] Specifies whether NTML or password authentication is used, or both, to authenticate login attempts. To use a specific authentication type, enter a (+) sign in front of the authentication type. To prevent a specific type of authentication from being used, enter a (-) sign in front of that type. /? Displays help on the command line. Notes

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.
• NTML is an authentication protocol for transactions between two computers, one or both of which are running Windows NT 4.0 or later earlier versions. Additionally, the NTML authentication protocol is used for computers that are not part of a domain, such as independent servers and workgroups.

To set the idle session timeout for the computer running the Telnet server

Syntax

tlntadmn [\\ remote_server] config [timeout=hh: mm: ss]

Options \\ remote_server Specifies the name of the server that you want to take control of. If no server is specified, the local server is used. timeout=hh: mm: ss Sets the elapsed time value in hours, minutes, and seconds. /? Displays help on the command line. Notes

• Using commands tlntadmn You can remotely administer a computer running Telnet Server if both computers are running Windows XP. Teams tlntadmn cannot be used to remotely administer a Telnet server running Windows 2000 from a computer running Windows XP.

• To switch from the Telnet client to command mode, at the Telnet command prompt, press CTRL keys+]. To return to the Telnet client, press ENTER.