Table of Contents
protocol
The command is used to communicate with another host using
the protocol. If is invoked without the argument, it enters command
mode, indicated by its prompt In this mode, it accepts and executes the
commands listed below. If it is invoked with arguments, it performs an
command with those arguments. Options: Specifies an 8-bit data path. This
causes an attempt to negotiate the option on both input and output. Stops
any character from being recognized as an escape character. If Kerberos
V5 authentication is being used, the option allows the local credentials
to be forwarded to the remote system, including any credentials that have
already been forwarded into the local environment. Specifies no automatic
login to the remote system. Specifies an 8-bit data path on output. This
causes the BINARY option to be negotiated on output. Sets the IP type-of-service
(TOS) option for the telnet connection to the value which can be a numeric
TOS value or, on systems that support it, a symbolic TOS name found in
the /etc/iptos file. Disables the type of authentication. Attempt automatic
login. Currently, this sends the user name via the variable of the option
if supported by the remote system. The name used is that of the current
user as returned by if it agrees with the current user ID, otherwise it
is the name associated with the user ID. Disables the reading of the user's
file. (See the command on this man page.) Sets the initial value of the
toggle to Sets the initial escape character to If is omitted, then
there will be no escape character. If Kerberos V5 authentication is being
used, the option allows the local credentials to be forwarded to the remote
system. If Kerberos authentication is being used, the option requests
that telnet obtain tickets for the remote host in realm realm instead of
the remote host's realm, as determined by When connecting to the remote
system, if the remote system understands the option, then will be sent
to the remote system as the value for the variable USER. This option implies
the option. This option may also be used with the command. Opens for
recording trace information. See the command below. Specifies a user interface
similar to In this mode, the escape character is set to the tilde (~)
character, unless modified by the -e option. Turns on encryption of the
data stream if possible. This option is not available outside of the United
States and Canada. Indicates the official name, an alias, or the Internet
address of a remote host. Indicates a port number (address of an application).
If a number is not specified, the default port is used. When in rlogin
mode, a line of the form ~. disconnects from the remote host; ~ is the
telnet escape character. Similarly, the line ~^Z suspends the telnet session.
The line ~^] escapes to the normal telnet escape prompt. Once a connection
has been opened, will attempt to enable the option. If this fails, then
will revert to one of two input modes: either qcharacter at a timeRq or
qold line by lineRq depending on what the remote system supports. When
is enabled, character processing is done on the local system, under the
control of the remote system. When input editing or character echoing is
to be disabled, the remote system will relay that information. The remote
system will also relay changes to any special characters that happen on
the remote system, so that they can take effect on the local system. In
qcharacter at a timeRq mode, most text typed is immediately sent to the
remote host for processing. In qold line by lineRq mode, all text is echoed
locally, and (normally) only completed lines are sent to the remote host.
The qlocal echo characterRq (initially q^ERq) may be used to turn off and
on the local echo (this would mostly be used to enter passwords without
the password being echoed). If the option is enabled, or if the toggle
is (the default for qold line by lineq; see below), the user's and characters
are trapped locally, and sent as protocol sequences to the remote side.
If has ever been enabled, then the user's and are also sent as protocol
sequences, and is sent as a instead of There are options (see and
below) which cause this action to flush subsequent output to the terminal
(until the remote host acknowledges the sequence) and flush previous terminal
input (in the case of and While connected to a remote host, command
mode may be entered by typing the qescape characterRq (initially q^]Rq).
When in command mode, the normal terminal editing conventions are available.
The following commands are available. Only enough of each command to uniquely
identify it need be typed (this is also true for arguments to the
and commands). The auth command manipulates the information sent through
the option. Valid arguments for the auth command are as follows: Disables
the specified type of authentication. To obtain a list of available types,
use the command. Enables the specified type of authentication. To obtain
a list of available types, use the command. Lists the current status of
the various types of authentication. Close a session and return to command
mode. Displays all, or some, of the and values (see below). The encrypt
command manipulates the information sent through the option. Note: Because
of export controls, the option is not supported outside of the United
States and Canada. Valid arguments for the encrypt command are as follows:
Disables the specified type of encryption. If you omit the input and
output, both input and output are disabled. To obtain a list of available
types, use the command. Enables the specified type of encryption. If you
omit input and output, both input and output are enabled. To obtain a list
of available types, use the command. This is the same as the command.
This is the same as the command. This is the same as the command. This
is the same as the command. Attempts to start encryption. If you omit
and both input and output are enabled. To obtain a list of available
types, use the command. Lists the current status of encryption. Stops
encryption. If you omit input and output, encryption is on both input and
output. Sets the default type of encryption to be used with later or
commands. The command is used to manipulate the the variables that my
be sent through the option. The initial set of variables is taken from
the users environment, with only the and variables being exported by
default. The variable is also exported if the or options are used.
Valid arguments for the command are: Define the variable to have a
value of Any variables defined by this command are automatically exported.
The may be enclosed in single or double quotes so that tabs and spaces
may be included. Remove from the list of environment variables. Mark the
variable to be exported to the remote side. Mark the variable to not
be exported unless explicitly asked for by the remote side. List the current
set of environment variables. Those marked with a will be sent automatically,
other variables will only be sent if explicitly requested. Prints out help
information for the command. Sends the option to the remote side. This
command is similar to a command; however, if the remote side does not
support the option, nothing happens. If, however, the remote side does
support the option, this command should cause the remote side to close
the connection. If the remote side also supports the concept of suspending
a user's session for later reattachment, the logout argument indicates that
you should terminate the session immediately. is one of several options,
depending on the state of the session. The remote host is asked for permission
to go into the requested mode. If the remote host is capable of entering
that mode, the requested mode will be entered. Disable the option, or,
if the remote side does not understand the option, then enter qcharacter
at a timeq mode. Enable the option, or, if the remote side does not understand
the option, then attempt to enter qold-line-by-lineq mode. Attempt to enable
(disable) the mode of the option. This requires that the option be
enabled. Attempt to enable (disable) the mode of the option. This requires
that the option be enabled. Attempt to enable (disable) the mode of
the option. This requires that the option be enabled. Attempt to enable
(disable) the mode of the option. This requires that the option be
enabled. Prints out help information for the command. Open a connection
to the named host. If no port number is specified, will attempt to contact
a server at the default port. The host specification may be either a host
name (see or an Internet address specified in the qdot notationRq (see
The option may be used to specify the user name to be passed to the remote
system via the option. When connecting to a non-standard port, omits any
automatic initiation of options. When the port number is preceded by a
minus sign, the initial option negotiation is done. After establishing a
connection, the file in the users home directory is opened. Lines beginning
with a # are comment lines. Blank lines are ignored. Lines that begin without
white space are the start of a machine entry. The first thing on the line
is the name of the machine that is being connected to. The rest of the
line, and successive lines that begin with white space are assumed to be
commands and are processed as if they had been typed in manually to the
command prompt. Close any open session and exit An end of file (in command
mode) will also close a session and exit. Sends one or more special character
sequences to the remote host. The following are the arguments which may
be specified (more than one argument may be specified at a time): Sends
the (Abort processes) sequence. Sends the (Abort Output) sequence, which
should cause the remote system to flush all output the remote system
the user's terminal. Sends the (Are You There) sequence, to which the remote
system may or may not choose to respond. Sends the (Break) sequence, which
may have significance to the remote system. Sends the (Erase Character)
sequence, which should cause the remote system to erase the last character
entered. Sends the (Erase Line) sequence, which should cause the remote
system to erase the line currently being entered. Sends the (End Of File)
sequence. Sends the (End of Record) sequence. Sends the current escape
character (initially q^Rq). Sends the (Go Ahead) sequence, which likely
has no significance to the remote system. If the remote side supports the
command, will send the subnegotiation to request that the server send
its current option status. Sends the (Interrupt Process) sequence, which
should cause the remote system to abort the currently running process.
Sends the (No OPeration) sequence. Sends the (SUSPend process) sequence.
Sends the sequence. This sequence causes the remote system to discard
all previously typed (but not yet read) input. This sequence is sent as
urgent data (and may not work if the remote system is a system -- if it
doesn't work, a lower case qrRq may be echoed on the terminal). Sends
the sequence. can be either a decimal number between 0 and 255, or a
symbolic name for a specific command. can also be either or to print
out help information, including a list of known symbolic names. Prints
out help information for the command. The command will set any one
of a number of variables to a specific value or to The special value
turns off the function associated with the variable, this is equivalent
to using the command. The command will disable or set to any of the specified
functions. The values of variables may be interrogated with the command.
The variables which may be set or unset, but not toggled, are listed here.
In addition, any of the variables for the command may be explicitly set
or unset using the and commands. If is in localchars mode, or is enabled,
and the status character is typed, a sequence (see preceding) is sent
to the remote host. The initial value for the "Are You There" character
is the terminal's status character. This is the value (initially q^ERq) which,
when in qline by lineRq mode, toggles between doing local echoing of entered
characters (for normal processing), and suppressing echoing of entered
characters (for entering, say, a password). If is operating in or qold
line by lineRq mode, entering this character as the first character on
a line will cause this character to be sent to the remote system. The initial
value of the eof character is taken to be the terminal's character. If
is in mode (see below), if is operating in qcharacter at a timeRq
mode, then when this character is typed, a sequence (see above) is sent
to the remote system. The initial value for the erase character is taken
to be the terminal's character. This is the escape character (initially
q^[Rq) which causes entry into command mode (when connected to a remote
system). If is in mode (see below) and the character is typed, a
sequence (see above) is sent to the remote host. The initial value for
the flush character is taken to be the terminal's character. If is operating
in these are the characters that, when typed, cause partial lines to be
forwarded to the remote system. The initial value for the forwarding characters
are taken from the terminal's eol and eol2 characters. If is in mode (see
below) and the character is typed, a sequence (see above) is sent
to the remote host. The initial value for the interrupt character is taken
to be the terminal's character. If is in mode (see below), if is
operating in qcharacter at a timeRq mode, then when this character is typed,
a sequence (see above) is sent to the remote system. The initial value
for the kill character is taken to be the terminal's character. If is
operating in or qold line by lineq mode, then this character is taken
to be the terminal's character. The initial value for the lnext character
is taken to be the terminal's character. If is in mode (see below)
and the character is typed, a sequence (see above) is sent to the remote
host. The initial value for the quit character is taken to be the terminal's
character. If is operating in or qold line by lineq mode, then this
character is taken to be the terminal's character. The initial value for
the reprint character is taken to be the terminal's character. This is
the rlogin escape character. If set, the normal escape character is ignored
unless it is preceded by this character at the beginning of a line. This
character, at the beginning of a line followed by a "." closes the connection;
when followed by a ^Z it suspends the telnet command. The initial state
is to disable the rlogin escape character. If the option has been enabled,
then this character is taken to be the terminal's character. The initial
value for the kill character is taken to be the terminal's character. If
the option has been enabled, then this character is taken to be the terminal's
character. The initial value for the kill character is taken to be the
terminal's character. If is in mode, or is enabled, and the character
is typed, a sequence (see above) is sent to the remote host. The initial
value for the suspend character is taken to be the terminal's character.
This is the file to which the output, caused by or tracing being will
be written. If it is set to then tracing information will be written to
standard output (the default). If is operating in or qold line by lineq
mode, then this character is taken to be the terminal's character. The initial
value for the worderase character is taken to be the terminal's character.
Displays the legal commands. The command (Set Local Characters) is
used to set or change the state of the special characters when the option
has been enabled. Special characters are characters that get mapped to
commands sequences (like or or line editing characters (like and
By default, the local special characters are exported. Verify the current
settings for the current special characters. The remote side is requested
to send all the current special character settings, and if there are any
discrepancies with the local side, the local side will switch to the remote
value. Switch to the local defaults for the special characters. The local
default characters are those of the local terminal at the time when was
started. Switch to the remote defaults for the special characters. The remote
default characters are those of the remote system at the time when the
connection was established. Prints out help information for the command.
Show the current status of This includes the peer one is connected to,
as well as the current mode. Toggle (between and various flags that control
how responds to events. These flags may be set explicitly to or using
the and commands listed above. More than one argument may be specified.
The state of these flags may be interrogated with the command. Valid arguments
are: Turns on debugging information for the authentication code. If
and are both then when the or characters are recognized (and transformed
into sequences; see above for details), refuses to display any data
on the user's terminal until the remote system acknowledges (via a option)
that it has processed those sequences. The initial value for this toggle
is if the terminal user had not done an "stty noflsh", otherwise (see
When the option is negotiated, by default the actual encryption (decryption)
of the data stream does not start automatically. The autoencrypt (autodecrypt)
command states that encryption of the output (input) stream should be enabled
as soon as possible. Note: Because of export controls, the option is
not supported outside the United States and Canada. If the remote side
supports the option attempts to use it to perform automatic authentication.
If the option is not supported, the user's login name are propagated through
the option. This command is the same as specifying option on the command.
If and are both then when either the or characters is typed (see
above for descriptions of the and characters), the resulting sequence
sent is followed by the sequence. This procedure cause the remote system
to begin throwing away all previously typed input until both of the sequences
have been read and acted upon. The initial value of this toggle is Enable
or disable the option on both input and output. Enable or disable the
option on input. Enable or disable the option on output. If this is
then carriage returns will be sent as If this is then carriage returns
will be send as The initial value for this toggle is Toggle carriage
return mode. When this mode is enabled, most carriage return characters
received from the remote host will be mapped into a carriage return followed
by a line feed. This mode does not affect those characters typed by the
user, only those received from the remote host. This mode is not very useful
unless the remote host only sends carriage return, but never line feed.
The initial value for this toggle is Toggles socket level debugging (useful
only to the The initial value for this toggle is Turns on debugging
information for the encryption code. If this is then the and characters
(see above) are recognized locally, and transformed into (hopefully) appropriate
control sequences (respectively and see above). The initial value
for this toggle is in qold line by lineRq mode, and in qcharacter at
a timeRq mode. When the option is enabled, the value of is ignored, and
assumed to always be If has ever been enabled, then is sent as and
suspend are sent as see above). Toggles the display of all network
data (in hexadecimal format). The initial value for this toggle is Toggles
the display of some internal protocol processing (having to do with options).
The initial value for this toggle is When the toggle is enabled, if
is enabled the output from the command will be formatted in a more user
readable format. Spaces are put between each character in the output, and
the beginning of any escape sequence is preceded by a '*' to aid in locating
them. When the skiprc toggle is skips the reading of the file in the
users home directory when connections are opened. The initial value for
this toggle is Toggles the display of all terminal data (in hexadecimal
format). The initial value for this toggle is When the toggle is prints
out a message each time encryption is enabled or disabled. The initial
value for this toggle is Note: Because of export controls, data encryption
is not supported outside of the United States and Canada. Displays the
legal commands. Suspend This command only works when the user is using
the Execute a single command in a subshell on the local system. If is
omitted, then an interactive subshell is invoked. Get help. With no arguments,
prints a help summary. If a command is specified, will print the help
information for just that command.
ENVIRONMENT
uses at least the and
environment variables. Other environment variables may be propagated to
the other side via the option.
user customized telnet
startup values
The command appeared in
On some remote systems,
echo has to be turned off manually when in qold line by lineRq mode. In
qold line by lineRq mode or the terminal's character is only recognized
(and sent to the remote system) when it is the first character on a line.
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