'\" te
.\" Copyright 1989 AT&T
.\" Copyright (C) 2004, Sun Microsystems, Inc. All Rights Reserved
.\" Copyright (c) 1983, 1990, 1993 The Regents of the University of California. All rights reserved.
.TH TELNET 1 "Aug 17, 2006"
.SH NAME
telnet \- user interface to a remote system using the TELNET protocol
.SH SYNOPSIS
.LP
.nf
\fBtelnet\fR [\fB-8EFKLacdfrx\fR] [\fB-X\fR \fIatype\fR] [\fB-e\fR \fIescape_char\fR]
     [\fB-k\fR \fIrealm\fR] [\fB-l\fR \fIuser\fR] [\fB-n\fR \fIfile\fR]
     [ [ [!] @hop1 [@hop2...] @] \fIhost\fR [\fIport\fR]]
.fi

.SH DESCRIPTION
.sp
.LP
The \fBtelnet\fR utility communicates with another host using the \fBTELNET\fR
protocol. If \fBtelnet\fR is invoked without arguments, it enters command mode,
indicated by its prompt, \fBtelnet>\fR. In this mode, it accepts and executes
its associated commands. See \fBUSAGE\fR. If it is invoked with arguments, it
performs an \fBopen\fR command with those arguments.
.sp
.LP
If, for example, a \fIhost\fR is specified as \fI@hop1@hop2@host\fR, the
connection goes through hosts \fIhop1\fR and \fIhop2\fR, using loose source
routing to end at \fIhost\fR. If a leading \fB!\fR is used, the connection
follows strict source routing. Notice that when \fBtelnet\fR uses IPv6, it can
only use loose source routing, and the connection ignores the \fB!\fR.
.sp
.LP
Once a connection has been opened, \fBtelnet\fR enters input mode. In this
mode, text typed is sent to the remote host. The input mode entered will be
either "line mode", "character at a time", or "old line by line", depending
upon what the remote system supports.
.sp
.LP
In "line mode", 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.
.sp
.LP
In "character at a time" mode, most text typed is immediately sent to the
remote host for processing.
.sp
.LP
In "old line by line" mode, all text is echoed locally, and (normally) only
completed lines are sent to the remote host. The "local echo character"
(initially \fB^E\fR) may be used to turn off and on the local echo. (Use this
mostly to enter passwords without the password being echoed.).
.sp
.LP
If the "line mode" option is enabled, or if the \fBlocalchars\fR toggle is
\fBTRUE\fR (the default in "old line by line" mode), the user's \fBquit\fR,
\fBintr\fR, and \fBflush\fR characters are trapped locally, and sent as
\fBTELNET\fR protocol sequences to the remote side. If "line mode" has ever
been enabled, then the user's \fBsusp\fR and \fBeof\fR are also sent as
\fBTELNET\fR protocol sequences. \fBquit\fR is then sent as a \fBTELNET
ABORT\fR instead of \fBBREAK\fR. The options \fBtoggle\fR \fBautoflush\fR and
\fBtoggle\fR \fBautosynch\fR cause this action to flush subsequent output to
the terminal (until the remote host acknowledges the \fBTELNET\fR sequence);
and to flush previous terminal input, in the case of \fBquit\fR and \fBintr\fR.
.sp
.LP
While connected to a remote host, the user can enter \fBtelnet\fR command mode
by typing the \fBtelnet\fR escape character (initially \fB^]\fR). When in
command mode, the normal terminal editing conventions are available. Pressing
RETURN at the \fBtelnet\fR command prompt causes \fBtelnet\fR to exit command
mode.
.SH OPTIONS
.sp
.LP
The following options are supported:
.sp
.ne 2
.na
\fB\fB-8\fR\fR
.ad
.sp .6
.RS 4n
Specifies an 8-bit data path. Negotiating the \fBTELNET BINARY\fR option is
attempted for both input and output.
.RE

.sp
.ne 2
.na
\fB\fB-a\fR\fR
.ad
.sp .6
.RS 4n
Attempts automatic login. This sends the user name by means of the \fBUSER\fR
variable of the \fBENVIRON\fR option, if supported by the remote system. The
name used is that of the current user as returned by \fBgetlogin\fR(3C) if it
agrees with the current user \fBID\fR. Otherwise, it is the name associated
with the user \fBID\fR.
.RE

.sp
.ne 2
.na
\fB\fB-c\fR\fR
.ad
.sp .6
.RS 4n
Disables the reading of the user's \fBtelnetrc\fR file. (See the \fBtoggle\fR
\fBskiprc\fR command on this reference page.)
.RE

.sp
.ne 2
.na
\fB\fB-d\fR\fR
.ad
.sp .6
.RS 4n
Sets the initial value of the \fBdebug\fR toggle to \fBTRUE\fR.
.RE

.sp
.ne 2
.na
\fB\fB-e\fR \fIescape_char\fR\fR
.ad
.sp .6
.RS 4n
Sets the initial escape character to \fIescape_char\fR. \fIescape_char\fR may
also be a two character sequence consisting of \fB^\fR (Control key) followed
by one character. If the second character is \fB?\fR, the \fBDEL\fR character
is selected. Otherwise, the second character is converted to a control
character and used as the escape character. If \fIescape_char\fR is defined as
the null string (that is, \fB-e\fR \fB\&''\fR), this is equivalent to
\fB-e\fR '\fB^@\fR' (Control-@). To specify that no character can be the escape
character, use the \fB-E\fR option.
.RE

.sp
.ne 2
.na
\fB\fB-E\fR\fR
.ad
.sp .6
.RS 4n
Stops any character from being recognized as an escape character.
.RE

.sp
.ne 2
.na
\fB\fB-f\fR\fR
.ad
.sp .6
.RS 4n
Forwards a copy of the local credentials to the remote system.
.RE

.sp
.ne 2
.na
\fB\fB-F\fR\fR
.ad
.sp .6
.RS 4n
Forwards a forwardable copy of the local credentials to the remote system.
.RE

.sp
.ne 2
.na
\fB\fB-k\fR \fIrealm\fR\fR
.ad
.sp .6
.RS 4n
If Kerberos authentication is being used, requests that \fBtelnet\fR obtain
tickets for the remote host in \fIrealm\fR instead of the remote host's default
realm as determined in \fBkrb5.conf\fR(5).
.RE

.sp
.ne 2
.na
\fB\fB-K\fR\fR
.ad
.sp .6
.RS 4n
Specifies no automatic login to the remote system.
.RE

.sp
.ne 2
.na
\fB\fB-l\fR \fIuser\fR\fR
.ad
.sp .6
.RS 4n
When connecting to a remote system that understands the \fBENVIRON\fR option,
then \fIuser\fR will be sent to the remote system as the value for the
\fBENVIRON\fR variable \fBUSER\fR.
.RE

.sp
.ne 2
.na
\fB\fB-L\fR\fR
.ad
.sp .6
.RS 4n
Specifies an 8-bit data path on output. This causes the \fBBINARY\fR option to
be negotiated on output.
.RE

.sp
.ne 2
.na
\fB\fB-n\fR \fItracefile\fR\fR
.ad
.sp .6
.RS 4n
Opens \fItracefile\fR for recording trace information. See the \fBset\fR
\fItracefile\fR command below.
.RE

.sp
.ne 2
.na
\fB\fB-r\fR\fR
.ad
.sp .6
.RS 4n
Specifies a user interface similar to \fBrlogin\fR. In this mode, the escape
character is set to the tilde (\fB~\fR) character, unless modified by the
\fB-e\fR option. The \fBrlogin\fR escape character is only recognized when it
is preceded by a carriage return. In this mode, the \fBtelnet\fR escape
character, normally '\fB^]\fR', must still precede a \fBtelnet\fR command. The
\fBrlogin\fR escape character can also be followed by '\fB\&.\er\fR'
or '\fB^Z\fR', and, like \fBrlogin\fR(1), closes or suspends the connection,
respectively. This option is an uncommitted interface and may change in the
future.
.RE

.sp
.ne 2
.na
\fB\fB-x\fR\fR
.ad
.sp .6
.RS 4n
Turns on encryption of the data stream. When this option is turned on,
\fBtelnet\fR will exit with an error if authentication cannot be negotiated or
if encryption cannot be turned on.
.RE

.sp
.ne 2
.na
\fB\fB-X\fR \fIatype\fR\fR
.ad
.sp .6
.RS 4n
Disables the \fIatype\fR type of authentication.
.RE

.SH USAGE
.SS "telnet Commands"
.sp
.LP
The commands described in this section are available with \fBtelnet\fR. It is
necessary to type only enough of each command to uniquely identify it. (This is
also true for arguments to the \fBmode\fR, \fBset\fR, \fBtoggle\fR,
\fBunset\fR, \fBenviron\fR, and \fBdisplay\fR commands.)
.sp
.ne 2
.na
\fB\fBauth\fR \fIargument\fR ...\fR
.ad
.sp .6
.RS 4n
The \fBauth\fR command manipulates the information sent through the
\fBTELNET\fR \fBAUTHENTICATE\fR option. Valid arguments for the \fBauth\fR
command are as follows:
.sp
.ne 2
.na
\fB\fBdisable\fR \fItype\fR\fR
.ad
.sp .6
.RS 4n
Disables the specified type of authentication. To obtain a list of available
types, use the \fBauth\fR \fBdisable ?\fR command.
.RE

.sp
.ne 2
.na
\fB\fBenable\fR \fItype\fR\fR
.ad
.sp .6
.RS 4n
Enables the specified type of authentication. To obtain a list of available
types, use the \fBauth\fR \fBenable ?\fR command.
.RE

.sp
.ne 2
.na
\fB\fBstatus\fR\fR
.ad
.sp .6
.RS 4n
Lists the current status of the various types of authentication.
.RE

.RE

.sp
.ne 2
.na
\fB\fBopen\fR [\fB\fR\fB-l\fR \fIuser\fR ] [ [!] @\fIhop1\fR
[@\fIhop2\fR ...]@\fIhost\fR [ \fIport\fR ]\fR
.ad
.sp .6
.RS 4n
Open a connection to the named host. If no port number is specified,
\fBtelnet\fR will attempt to contact a \fBTELNET\fR server at the default port.
The host specification may be either a host name (see \fBhosts\fR(5)) or an
Internet address specified in the "dot notation" (see \fBinet\fR(4P) or
\fBinet6\fR(4P)). If the \fIhost\fR is specified as \fI@hop1@hop2@host\fR, the
connection goes through hosts \fIhop1\fR and \fIhop2\fR, using loose source
routing to end at \fIhost\fR. The \fB@\fR symbol is required as a separator
between the hosts specified. If a leading \fB!\fR is used with IPv4, the
connection follows strict source routing.
.sp
The \fB-l\fR option passes the \fIuser\fR as the value of the \fBENVIRON\fR
variable \fBUSER\fR to the remote system.
.RE

.sp
.ne 2
.na
\fB\fBclose\fR\fR
.ad
.sp .6
.RS 4n
Close any open \fBTELNET\fR session and exit \fBtelnet\fR. An \fBEOF\fR (in
command mode) will also close a session and exit.
.RE

.sp
.ne 2
.na
\fB\fBencrypt\fR\fR
.ad
.sp .6
.RS 4n
The encrypt command manipulates the information sent through the \fBTELNET\fR
\fBENCRYPT\fR option.
.sp
Valid arguments for the encrypt command are as follows:
.sp
.ne 2
.na
\fB\fBdisable\fR \fItype\fR [\fBinput\fR|\fBoutput\fR]\fR
.ad
.sp .6
.RS 4n
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 \fBencrypt\fR \fBdisable ?\fR command.
.RE

.sp
.ne 2
.na
\fB\fBenable\fR \fItype\fR [\fBinput\fR|\fBoutput\fR]\fR
.ad
.sp .6
.RS 4n
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
\fBencrypt\fR \fBenable ?\fR command.
.RE

.sp
.ne 2
.na
\fB\fBinput\fR\fR
.ad
.sp .6
.RS 4n
This is the same as the \fBencrypt\fR \fBstart input\fR command.
.RE

.sp
.ne 2
.na
\fB\fB-input\fR\fR
.ad
.sp .6
.RS 4n
This is the same as the \fBencrypt\fR \fBstop input\fR command.
.RE

.sp
.ne 2
.na
\fB\fBoutput\fR\fR
.ad
.sp .6
.RS 4n
This is the same as the \fBencrypt\fR \fBstart output\fR command.
.RE

.sp
.ne 2
.na
\fB\fB-output\fR\fR
.ad
.sp .6
.RS 4n
This is the same as the \fBencrypt\fR \fBstop output\fR command.
.RE

.sp
.ne 2
.na
\fB\fBstart\fR [\fBinput\fR|\fBoutput\fR]\fR
.ad
.sp .6
.RS 4n
Attempts to start encryption. If you omit input and output, both input and
output are enabled. To obtain a list of available types, use the \fBencrypt\fR
\fBenable ?\fR command.
.RE

.sp
.ne 2
.na
\fB\fBstatus\fR\fR
.ad
.sp .6
.RS 4n
Lists the current status of encryption.
.RE

.sp
.ne 2
.na
\fB\fBstop\fR [\fBinput\fR|\fBoutput\fR]\fR
.ad
.sp .6
.RS 4n
Stops encryption. If you omit input and output, encryption is on both input and
output.
.RE

.sp
.ne 2
.na
\fB\fBtype\fR \fItype\fR\fR
.ad
.sp .6
.RS 4n
Sets the default type of encryption to be used with later \fBencrypt\fR
\fBstart\fR or \fBencrypt\fR \fBstop\fR commands.
.RE

.RE

.sp
.ne 2
.na
\fB\fBquit\fR\fR
.ad
.sp .6
.RS 4n
Same as \fBclose\fR.
.RE

.sp
.ne 2
.na
\fB\fBz\fR\fR
.ad
.sp .6
.RS 4n
Suspend \fBtelnet\fR. This command only works when the user is using a shell
that supports job control, such as \fBsh\fR(1).
.RE

.sp
.ne 2
.na
\fB\fBmode\fR \fItype\fR\fR
.ad
.sp .6
.RS 4n
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. The argument \fItype\fR is one of the following:
.sp
.ne 2
.na
\fB\fBcharacter\fR\fR
.ad
.sp .6
.RS 4n
Disable the \fBTELNET LINEMODE\fR option, or, if the remote side does not
understand the \fBLINEMODE\fR option, then enter "character at a time" mode.
.RE

.sp
.ne 2
.na
\fB\fBline\fR\fR
.ad
.sp .6
.RS 4n
Enable the \fBTELNET LINEMODE\fR option, or, if the remote side does not
understand the \fBLINEMODE\fR option, then attempt to enter "old-line-by-line"
mode.
.RE

.sp
.ne 2
.na
\fB\fBisig\fR (\fB-isig\fR)\fR
.ad
.sp .6
.RS 4n
Attempt to enable (disable) the \fBTRAPSIG\fR mode of the \fBLINEMODE\fR
option. This requires that the \fBLINEMODE\fR option be enabled.
.RE

.sp
.ne 2
.na
\fB\fBedit\fR (\fB-edit\fR)\fR
.ad
.sp .6
.RS 4n
Attempt to enable (disable) the \fBEDIT\fR mode of the \fBLINEMODE\fR option.
This requires that the \fBLINEMODE\fR option be enabled.
.RE

.sp
.ne 2
.na
\fB\fBsofttabs\fR (\fB-softtabs\fR)\fR
.ad
.sp .6
.RS 4n
Attempt to enable (disable) the \fBSOFT_TAB\fR mode of the \fBLINEMODE\fR
option. This requires that the \fBLINEMODE\fR option be enabled.
.RE

.sp
.ne 2
.na
\fB\fBlitecho\fR (\fB-litecho\fR)\fR
.ad
.sp .6
.RS 4n
Attempt to enable (disable) the \fBLIT_ECHO\fR mode of the \fBLINEMODE\fR
option. This requires that the \fBLINEMODE\fR option be enabled.
.RE

.sp
.ne 2
.na
\fB\fB?\fR\fR
.ad
.sp .6
.RS 4n
Prints out help information for the \fBmode\fR command.
.RE

.RE

.sp
.ne 2
.na
\fB\fBstatus\fR\fR
.ad
.sp .6
.RS 4n
Show the current status of \fBtelnet\fR. This includes the peer one is
connected to, as well as the current mode.
.RE

.sp
.ne 2
.na
\fB\fBdisplay\fR\fR
.ad
.sp .6
.RS 4n
[\fIargument\fR\|.\|.\|.\|] Display all, or some, of the \fBset\fR and
\fBtoggle\fR values (see \fBtoggle\fR \fIargument\fR.\|.\|.).
.RE

.sp
.ne 2
.na
\fB\fB?\fR\fR
.ad
.sp .6
.RS 4n
[\fIcommand\fR] Get help. With no arguments, \fBtelnet\fR prints a help
summary. If a command is specified, \fBtelnet\fR will print the help
information for just that command.
.RE

.sp
.ne 2
.na
\fB\fBsend\fR \fIargument\fR\fB\|.\|.\|.\fR\fR
.ad
.sp .6
.RS 4n
Send one or more special character sequences to the remote host. The following
are the arguments that can be specified (more than one argument may be
specified at a time):
.sp
.ne 2
.na
\fB\fBescape\fR\fR
.ad
.sp .6
.RS 4n
Send the current \fBtelnet\fR escape character (initially \fB^]\fR).
.RE

.sp
.ne 2
.na
\fB\fBsynch\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET SYNCH\fR sequence. This sequence discards all previously
typed, but not yet read, input on the remote system. This sequence is sent as
\fBTCP\fR urgent data and may not work if the remote system is a 4.2 \fBBSD\fR
system. If it does not work, a lowercase "r" may be echoed on the terminal.
.RE

.sp
.ne 2
.na
\fB\fBbrk\fR or \fBbreak\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET BRK\fR (Break) sequence, which may have significance to the
remote system.
.RE

.sp
.ne 2
.na
\fB\fBip\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET IP\fR (Interrupt Process) sequence, which aborts the
currently running process on the remote system.
.RE

.sp
.ne 2
.na
\fB\fBabort\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET ABORT\fR (Abort Process) sequence.
.RE

.sp
.ne 2
.na
\fB\fBao\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET AO\fR (Abort Output) sequence, which flushes all output from
the remote system to the user's terminal.
.RE

.sp
.ne 2
.na
\fB\fBayt\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET AYT\fR (Are You There) sequence, to which the remote system
may or may not respond.
.RE

.sp
.ne 2
.na
\fB\fBec\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET EC\fR (Erase Character) sequence, which erases the last
character entered.
.RE

.sp
.ne 2
.na
\fB\fBel\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET EL\fR (Erase Line) sequence, which should cause the remote
system to erase the line currently being entered.
.RE

.sp
.ne 2
.na
\fB\fBeof\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET EOF\fR (End Of File) sequence.
.RE

.sp
.ne 2
.na
\fB\fBeor\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET EOR\fR (End Of Record) sequence.
.RE

.sp
.ne 2
.na
\fB\fBga\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET GA\fR (Go Ahead) sequence, which probably has no
significance for the remote system.
.RE

.sp
.ne 2
.na
\fB\fBgetstatus\fR\fR
.ad
.sp .6
.RS 4n
If the remote side supports the \fBTELNET STATUS\fR command, \fBgetstatus\fR
will send the subnegotiation to request that the server send its current option
status.
.RE

.sp
.ne 2
.na
\fB\fBnop\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET NOP\fR (No Operation) sequence.
.RE

.sp
.ne 2
.na
\fB\fBsusp\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET SUSP\fR (Suspend Process) sequence.
.RE

.sp
.ne 2
.na
\fB\fBdo\fR \fIoption\fR\fR
.ad
.br
.na
\fB\fBdont\fR \fIoption\fR\fR
.ad
.br
.na
\fB\fBwill\fR \fIoption\fR\fR
.ad
.br
.na
\fB\fBwont\fR \fIoption\fR\fR
.ad
.sp .6
.RS 4n
Send the \fBTELNET\fR protocol option negotiation indicated. Option may be the
text name of the protocol option, or the number corresponding to the option.
The command will be silently ignored if the option negotiation indicated is not
valid in the current state. If the \fIoption\fR is given as \fBhelp\fR or
\fB?\fR, the list of option names known is listed. This command is mostly
useful for unusual debugging situations.
.RE

.sp
.ne 2
.na
\fB\fB?\fR\fR
.ad
.sp .6
.RS 4n
Print out help information for the \fBsend\fR command.
.RE

.RE

.sp
.ne 2
.na
\fB\fBset\fR \fIargument\fR [\fIvalue\fR]\fR
.ad
.br
.na
\fB\fBunset\fR \fIargument\fR\fR
.ad
.sp .6
.RS 4n
Set any one of a number of \fBtelnet\fR variables to a specific value. The
special value \fBoff\fR turns off the function associated with the variable.
The values of variables may be interrogated with the \fBdisplay\fR command. If
\fIvalue\fR is omitted, the value is taken to be true, or "on". If the
\fBunset\fR form is used, the value is taken to be false, or \fBoff\fR. The
variables that may be specified are:
.sp
.ne 2
.na
\fB\fBecho\fR\fR
.ad
.sp .6
.RS 4n
This is the value (initially \fB^E\fR) that, when in "line by line" mode,
toggles between local echoing of entered characters for normal processing, and
suppressing echoing of entered characters, for example, entering a password.
.RE

.sp
.ne 2
.na
\fB\fBescape\fR\fR
.ad
.sp .6
.RS 4n
This is the \fBtelnet\fR escape character (initially \fB^]\fR) that enters
\fBtelnet\fR command mode when connected to a remote system.
.RE

.sp
.ne 2
.na
\fB\fBinterrupt\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is in \fBlocalchars\fR mode (see \fBtoggle\fR,
\fBlocalchars\fR) and the \fBinterrupt\fR character is typed, a \fBTELNET IP\fR
sequence (see \fBsend\fR and \fBip\fR) is sent to the remote host. The initial
value for the interrupt character is taken to be the terminal's \fBintr\fR
character.
.RE

.sp
.ne 2
.na
\fB\fBquit\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is in \fBlocalchars\fR mode and the \fBquit\fR character is
typed, a \fBTELNET BRK\fR sequence (see \fBsend\fR, \fBbrk\fR) is sent to the
remote host. The initial value for the quit character is taken to be the
terminal's \fBquit\fR character.
.RE

.sp
.ne 2
.na
\fB\fBflushoutput\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is in \fBlocalchars\fR mode and the \fBflushoutput\fR character
is typed, a \fBTELNET AO\fR sequence (see \fBsend\fR, \fBao\fR) is sent to the
remote host. The initial value for the flush character is taken to be the
terminal's \fBflush\fR character.
.RE

.sp
.ne 2
.na
\fB\fBerase\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is in \fBlocalchars\fR mode \fIand\fR operating in "character
at a time" mode, then when the \fBerase\fR character is typed, a \fBTELNET
EC\fR sequence (see \fBsend\fR, \fBec\fR) is sent to the remote system. The
initial value for the \fBerase\fR character is taken to be the terminal's
\fBerase\fR character.
.RE

.sp
.ne 2
.na
\fB\fBkill\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is in \fBlocalchars\fR mode \fIand\fR operating in "character
at a time" mode, then when the \fBkill\fR character is typed, a \fBTELNET EL\fR
sequence (see \fBsend\fR, \fBel\fR) is sent to the remote system. The initial
value for the \fBkill\fR character is taken to be the terminal's \fBkill\fR
character.
.RE

.sp
.ne 2
.na
\fB\fBeof\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is operating in "line by line"/ mode, entering the \fBeof\fR
character as the first character on a line sends this character to the remote
system. The initial value of \fBeof\fR is taken to be the terminal's \fBeof\fR
character.
.RE

.sp
.ne 2
.na
\fB\fBayt\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is in \fBlocalchars\fR mode, or \fBLINEMODE\fR is enabled, and
the status character is typed, a \fBTELNET AYT\fR ("Are You There") sequence is
sent to the remote host. (See \fBsend\fR, \fBayt\fR above.) The initial value
for \fBayt\fR is the terminal's status character.
.RE

.sp
.ne 2
.na
\fB\fBforw1\fR\fR
.ad
.br
.na
\fB\fBforw2\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is operating in \fBLINEMODE,\fR and the \fBforw1\fR or
\fBforw2\fR characters are typed, this causes the forwarding of partial lines
to the remote system. The initial values for the forwarding characters come
from the terminal's \fBeol\fR and \fBeol2\fR characters.
.RE

.sp
.ne 2
.na
\fB\fBlnext\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is operating in \fBLINEMODE\fR or "old line by line" mode, then
the \fBlnext\fR character is assumed to be the terminal's \fBlnext\fR
character. The initial value for the \fBlnext\fR character is taken to be the
terminal's \fBlnext\fR character.
.RE

.sp
.ne 2
.na
\fB\fBreprint\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is operating in \fBLINEMODE\fR or "old line by line" mode, then
the \fBreprint\fR character is assumed to be the terminal's \fBreprint\fR
character. The initial value for \fBreprint\fR is taken to be the terminal's
\fBreprint\fR character.
.RE

.sp
.ne 2
.na
\fB\fBrlogin\fR\fR
.ad
.sp .6
.RS 4n
This is the \fBrlogin\fR escape character. If set, the normal \fBtelnet\fR
escape character is ignored, unless it is preceded by this character at the
beginning of a line. The \fBrlogin\fR character, at the beginning of a line
followed by a "\fB\&.\fR" closes the connection. When followed by a \fB^Z\fR,
the \fBrlogin\fR command suspends the \fBtelnet\fR command. The initial state
is to disable the \fBrlogin\fR escape character.
.RE

.sp
.ne 2
.na
\fB\fBstart\fR\fR
.ad
.sp .6
.RS 4n
If the \fBTELNET TOGGLE-FLOW-CONTROL\fR option has been enabled, then the
\fBstart\fR character is taken to be the terminal's \fBstart\fR character. The
initial value for the \fBkill\fR character is taken to be the terminal's
\fBstart\fR character.
.RE

.sp
.ne 2
.na
\fB\fBstop\fR\fR
.ad
.sp .6
.RS 4n
If the \fBTELNET TOGGLE-FLOW-CONTROL\fR option has been enabled, then the
\fBstop\fR character is taken to be the terminal's \fBstop\fR character. The
initial value for the \fBkill\fR character is taken to be the terminal's
\fBstop\fR character.
.RE

.sp
.ne 2
.na
\fB\fBsusp\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is in \fBlocalchars\fR mode, or \fBLINEMODE\fR is enabled, and
the \fBsuspend\fR character is typed, a \fBTELNET SUSP\fR sequence (see
\fBsend\fR, \fBsusp\fR above) is sent to the remote host. The initial value for
the \fBsuspend\fR character is taken to be the terminal's \fBsuspend\fR
character.
.RE

.sp
.ne 2
.na
\fB\fBtracefile\fR\fR
.ad
.sp .6
.RS 4n
This is the file to which the output, generated when the \fBnetdata\fR or the
\fBdebug\fR option is \fBTRUE\fR, will be written. If \fBtracefile\fR is set to
"\fB-\fR", then tracing information will be written to standard output (the
default).
.RE

.sp
.ne 2
.na
\fB\fBworderase\fR\fR
.ad
.sp .6
.RS 4n
If \fBtelnet\fR is operating in \fBLINEMODE\fR or "old line by line" mode, then
this character is taken to be the terminal's \fBworderase\fR character. The
initial value for the \fBworderase\fR character is taken to be the terminal's
\fBworderase\fR character.
.RE

.sp
.ne 2
.na
\fB\fB?\fR\fR
.ad
.sp .6
.RS 4n
Displays the legal \fBset\fR and \fBunset\fR commands.
.RE

.RE

.sp
.ne 2
.na
\fB\fBslc\fR \fIstate\fR\fR
.ad
.sp .6
.RS 4n
The \fBslc\fR (Set Local Characters) command is used to set or change the state
of special characters when the \fBTELNET LINEMODE\fR option has been enabled.
Special characters are characters that get mapped to \fBTELNET\fR commands
sequences (like \fBip\fR or \fBquit\fR) or line editing characters (like
\fBerase\fR and \fBkill\fR). By default, the local special characters are
exported. The following values for \fIstate\fR are valid:
.sp
.ne 2
.na
\fB\fBcheck\fR\fR
.ad
.sp .6
.RS 4n
Verifies the settings for the current special characters. The remote side is
requested to send all the current special character settings. If there are any
discrepancies with the local side, the local settings will switch to the remote
values.
.RE

.sp
.ne 2
.na
\fB\fBexport\fR\fR
.ad
.sp .6
.RS 4n
Switches to the local defaults for the special characters. The local default
characters are those of the local terminal at the time when \fBtelnet\fR was
started.
.RE

.sp
.ne 2
.na
\fB\fBimport\fR\fR
.ad
.sp .6
.RS 4n
Switches to the remote defaults for the special characters. The remote default
characters are those of the remote system at the time when the \fBTELNET\fR
connection was established.
.RE

.sp
.ne 2
.na
\fB\fB?\fR\fR
.ad
.sp .6
.RS 4n
Prints out help information for the \fBslc\fR command.
.RE

.RE

.sp
.ne 2
.na
\fB\fBtoggle\fR \fIargument\fR...\fR
.ad
.sp .6
.RS 4n
Toggle between \fBTRUE\fR and \fBFALSE\fR the various flags that control how
\fBtelnet\fR responds to events. More than one argument may be specified. The
state of these flags may be interrogated with the \fBdisplay\fR command. Valid
arguments are:
.sp
.ne 2
.na
\fB\fBauthdebug\fR\fR
.ad
.RS 20n
Turns on debugging information for the authentication code.
.RE

.sp
.ne 2
.na
\fB\fBautodecrypt\fR\fR
.ad
.RS 20n
When the \fBTELNET\fR \fBENCRYPT\fR 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.
.RE

.sp
.ne 2
.na
\fB\fBautologin\fR\fR
.ad
.RS 20n
If the remote side supports the \fBTELNET\fR \fBAUTHENTICATION\fR option,
\fBtelnet\fR attempts to use it to perform automatic authentication. If the
\fBAUTHENTICATION\fR option is not supported, the user's login name is
propagated through the \fBTELNET\fR \fBENVIRON\fR option. This command is the
same as specifying the \fB-a\fR option on the \fBopen\fR command.
.RE

.sp
.ne 2
.na
\fB\fBautoflush\fR\fR
.ad
.RS 20n
If \fBautoflush\fR and \fBlocalchars\fR are both \fBTRUE,\fR then when the
\fBao\fR, \fBintr\fR, or \fBquit\fR characters are recognized (and transformed
into \fBTELNET\fR sequences; see \fBset\fR for details), \fBtelnet\fR refuses
to display any data on the user's terminal until the remote system acknowledges
(using a \fBTELNET\fR Timing Mark option) that it has processed those
\fBTELNET\fR sequences. The initial value for this toggle is \fBTRUE\fR if the
terminal user has not done an "stty noflsh". Otherwise, the value is
\fBFALSE\fR (see \fBstty\fR(1)).
.RE

.sp
.ne 2
.na
\fB\fBautosynch\fR\fR
.ad
.RS 20n
If \fBautosynch\fR and \fBlocalchars\fR are both \fBTRUE\fR, then when either
the \fBinterrupt\fR or \fBquit\fR characters are typed (see \fBset\fR for
descriptions of \fBinterrupt\fR and \fBquit\fR), the resulting \fBTELNET\fR
sequence sent is followed by the \fBTELNET SYNCH\fR sequence. This procedure
\fIshould\fR cause the remote system to begin throwing away all previously
typed input until both of the \fBTELNET\fR sequences have been read and acted
upon. The initial value of this toggle is \fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fBbinary\fR\fR
.ad
.RS 20n
Enable or disable the \fBTELNET BINARY\fR option on both input and output.
.RE

.sp
.ne 2
.na
\fB\fBinbinary\fR\fR
.ad
.RS 20n
Enable or disable the \fBTELNET BINARY\fR option on input.
.RE

.sp
.ne 2
.na
\fB\fBoutbinary\fR\fR
.ad
.RS 20n
Enable or disable the \fBTELNET BINARY\fR option on output.
.RE

.sp
.ne 2
.na
\fB\fBcrlf\fR\fR
.ad
.RS 20n
Determines how carriage returns are sent. If the value is \fBTRUE\fR, then
carriage returns will be sent as \fB<CR><LF>\fR\&. If the value is \fBFALSE\fR,
then carriage returns will be send as \fB<CR><NUL>\fR\&. The initial value for
this toggle is \fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fBcrmod\fR\fR
.ad
.RS 20n
Toggle RETURN mode. When this mode is enabled, most RETURN characters received
from the remote host will be mapped into a 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 useful only for remote hosts that send
RETURN but never send LINEFEED. The initial value for this toggle is
\fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fBdebug\fR\fR
.ad
.RS 20n
Toggle socket level debugging (only available to the super-user). The initial
value for this toggle is \fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fBencdebug\fR\fR
.ad
.RS 20n
Turns on debugging information for the encryption code.
.RE

.sp
.ne 2
.na
\fB\fBlocalchars\fR\fR
.ad
.RS 20n
If this toggle is \fBTRUE\fR, then the \fBflush\fR, \fBinterrupt\fR,
\fBquit\fR, \fBerase\fR, and \fBkill\fR characters (see \fBset\fR) are
recognized locally, and transformed into appropriate \fBTELNET\fR control
sequences, respectively \fBao\fR, \fBip\fR, \fBbrk\fR, \fBec\fR, and \fBel\fR
(see \fBsend\fR). The initial value for this toggle is \fBTRUE\fR in "line by
line" mode, and \fBFALSE\fR in "character at a time" mode. When the
\fBLINEMODE\fR option is enabled, the value of \fBlocalchars\fR is ignored, and
assumed always to be \fBTRUE\fR. If \fBLINEMODE\fR has ever been enabled, then
\fBquit\fR is sent as \fBabort\fR, and \fBeof\fR and \fBsuspend\fR are sent as
\fBeof\fR and \fBsusp\fR (see \fBsend\fR above).
.RE

.sp
.ne 2
.na
\fB\fBnetdata\fR\fR
.ad
.RS 20n
Toggle the display of all network data (in hexadecimal format). The initial
value for this toggle is \fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fBoptions\fR\fR
.ad
.RS 20n
Toggle the display of some internal \fBTELNET\fR protocol processing (having to
do with \fBtelnet\fR options). The initial value for this toggle is
\fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fBprettydump\fR\fR
.ad
.RS 20n
When the \fBnetdata\fR toggle is enabled, if \fBprettydump\fR is enabled, the
output from the \fBnetdata\fR command will be formatted in a more user readable
format. Spaces are put between each character in the output. The beginning of
any \fBTELNET\fR escape sequence is preceded by an asterisk (\fB*\fR) to aid in
locating them.
.RE

.sp
.ne 2
.na
\fB\fBskiprc\fR\fR
.ad
.RS 20n
When the \fBskiprc\fR toggle is \fBTRUE\fR, \fBTELNET\fR skips the reading of
the \fB\&.telnetrc\fR file in the user's home directory when connections are
opened. The initial value for this toggle is \fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fBtermdata\fR\fR
.ad
.RS 20n
Toggles the display of all terminal data (in hexadecimal format). The initial
value for this toggle is \fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fBverbose_encrypt\fR\fR
.ad
.RS 20n
When the \fBverbose_encrypt\fR flag is \fBTRUE\fR, \fBTELNET\fR prints out a
message each time encryption is enabled or disabled. The initial value for this
toggle is \fBFALSE\fR.
.RE

.sp
.ne 2
.na
\fB\fB?\fR\fR
.ad
.RS 20n
Display the legal \fBtoggle\fR commands.
.RE

.RE

.sp
.ne 2
.na
\fB\fBenviron\fR \fIargument\|.\|.\|.\fR\fR
.ad
.sp .6
.RS 4n
The \fBenviron\fR command is used to manipulate variables that may be sent
through the \fBTELNET ENVIRON\fR option. The initial set of variables is taken
from the users environment. Only the \fBDISPLAY\fR and \fBPRINTER\fR variables
are exported by default. Valid arguments for the \fBenviron\fR command are:
.sp
.ne 2
.na
\fB\fBdefine\fR \fIvariable value\fR\fR
.ad
.sp .6
.RS 4n
Define \fIvariable\fR to have a value of \fIvalue\fR. Any variables defined by
this command are automatically exported. The \fIvalue\fR may be enclosed in
single or double quotes, so that tabs and spaces may be included.
.RE

.sp
.ne 2
.na
\fB\fBundefine\fR \fIvariable\fR\fR
.ad
.sp .6
.RS 4n
Remove \fIvariable\fR from the list of environment variables.
.RE

.sp
.ne 2
.na
\fB\fBexport\fR \fIvariable\fR\fR
.ad
.sp .6
.RS 4n
Mark the \fIvariable\fR to be exported to the remote side.
.RE

.sp
.ne 2
.na
\fB\fBunexport\fR \fIvariable\fR\fR
.ad
.sp .6
.RS 4n
Mark the \fIvariable\fR to not be exported unless explicitly requested by the
remote side.
.RE

.sp
.ne 2
.na
\fB\fBlist\fR\fR
.ad
.sp .6
.RS 4n
List the current set of environment variables. Those marked with an asterisk
(\fB*\fR) will be sent automatically. Other variables will be sent only if
explicitly requested.
.RE

.sp
.ne 2
.na
\fB\fB?\fR\fR
.ad
.sp .6
.RS 4n
Prints out help information for the \fBenviron\fR command.
.RE

.RE

.sp
.ne 2
.na
\fB\fBlogout\fR\fR
.ad
.sp .6
.RS 4n
Sends the \fBtelnet logout\fR option to the remote side. This command is
similar to a \fBclose\fR command. However, if the remote side does not support
the \fBlogout\fR option, nothing happens. If, however, the remote side does
support the \fBlogout\fR option, this command should cause the remote side to
close the \fBTELNET\fR connection. If the remote side also supports the concept
of suspending a user's session for later reattachment, the \fBlogout\fR
argument indicates that the remote side should terminate the session
immediately.
.RE

.SH FILES
.sp
.ne 2
.na
\fB\fB$HOME/.telnetrc\fR\fR
.ad
.RS 19n
file that contains commands to be executed before initiating a \fBtelnet\fR
session
.RE

.SH SEE ALSO
.sp
.LP
.BR rlogin (1),
.BR sh (1),
.BR stty (1),
.BR getlogin (3C),
.BR inet (4P),
.BR inet6 (4P),
.BR hosts (5),
.BR krb5.conf (5),
.BR nologin (5),
.BR telnetrc (5),
.BR attributes (7)
.SH DIAGNOSTICS
.sp
.ne 2
.na
\fB\fBNO LOGINS: System going down in\fR \fIN\fR \fBminutes\fR\fR
.ad
.sp .6
.RS 4n
The machine is in the process of being shut down and logins have been disabled.
.RE

.SH NOTES
.sp
.LP
On some remote systems, echo has to be turned off manually when in "line by
line" mode.
.sp
.LP
In "old line by line" mode, or \fBLINEMODE\fR, the terminal's \fBEOF\fR
character is only recognized (and sent to the remote system) when it is the
first character on a line.
.sp
.LP
The \fBtelnet\fR protocol only uses single DES for session
protection\(emclients request service tickets with single DES session keys. The
KDC must know that host service principals that offer the \fBtelnet\fR service
support single DES, which, in practice, means that such principals must have
single DES keys in the KDC database.