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32 .\" @(#)telnet.1 8.6 (Berkeley) 6/1/94
33 .\" $FreeBSD: src/crypto/telnet/telnet/telnet.1,v 1.4.2.9 2002/04/13 10:59:08 markm Exp $
34 .\" $DragonFly: src/crypto/telnet/telnet/telnet.1,v 1.2 2003/06/17 04:24:37 dillon Exp $
41 .Nd user interface to the
46 .Op Fl 468EFKLNacdfruxy
49 .Op Fl e Ar escapechar
62 is used to communicate with another host using the
67 is invoked without the
69 argument, it enters command mode,
70 indicated by its prompt
72 In this mode, it accepts and executes the commands listed below.
73 If it is invoked with arguments, it performs an
75 command with those arguments.
78 .Bl -tag -width indent
82 to use IPv4 addresses only.
86 to use IPv6 addresses only.
88 Specifies an 8-bit data path. This causes an attempt to
91 option on both input and output.
93 Stops any character from being recognized as an escape character.
95 If Kerberos V5 authentication is being used, the
97 option allows the local credentials to be forwarded
98 to the remote system, including any credentials that
99 have already been forwarded into the local environment.
101 Specifies no automatic login to the remote system.
103 Specifies an 8-bit data path on output. This causes the
105 option to be negotiated on output.
107 Prevents IP address to name lookup when destination host is given
110 Sets the IP type-of-service (TOS) option for the telnet
111 connection to the value
113 which can be a numeric TOS value
114 or, on systems that support it, a symbolic
115 TOS name found in the
121 type of authentication.
123 Attempt automatic login.
124 This is now the default, so this option is ignored.
125 Currently, this sends the user name via the
130 option if supported by the remote system.
131 The name used is that of the current user as returned by
133 if it agrees with the current user ID,
134 otherwise it is the name associated with the user ID.
136 Disables the reading of the user's
140 command on this man page.)
142 Sets the initial value of the
146 .It Fl e Ar escapechar
154 there will be no escape character.
156 If Kerberos V5 authentication is being used, the
158 option allows the local credentials to be forwarded to the remote system.
160 If Kerberos authentication is being used, the
164 obtain tickets for the remote host in
167 instead of the remote host's realm, as determined by
168 .Xr krb_realmofhost 3 .
170 When connecting to the remote system, if the remote system
175 will be sent to the remote system as the value for the variable
177 This option implies the
180 This option may also be used with the
183 .It Fl n Ar tracefile
186 for recording trace information.
191 Specifies a user interface similar to
194 mode, the escape character is set to the tilde (~) character,
195 unless modified by the
199 Set the source IP address for the
203 which can be an IP address or a host name.
209 addresses only (e.g.,
211 domain sockets, accessed with a file path).
213 Turns on encryption of the data stream if possible.
214 This is now the default, so this option is ignored.
216 Suppresses encryption of the data stream.
218 Indicates the official name, an alias, or the Internet address
225 establishes a connection to the corresponding named socket.
227 Indicates a port number (address of an application). If a number is
228 not specified, the default
233 When in rlogin mode, a line of the form ~. disconnects from the
234 remote host; ~ is the
237 Similarly, the line ~^Z suspends the
240 The line ~^] escapes to the normal
244 Once a connection has been opened,
246 will attempt to enable the
251 will revert to one of two input modes:
252 either \*(Lqcharacter at a time\*(Rq
253 or \*(Lqold line by line\*(Rq
254 depending on what the remote system supports.
258 is enabled, character processing is done on the
259 local system, under the control of the remote system. When input
260 editing or character echoing is to be disabled, the remote system
261 will relay that information. The remote system will also relay
262 changes to any special characters that happen on the remote
263 system, so that they can take effect on the local system.
265 In \*(Lqcharacter at a time\*(Rq mode, most
266 text typed is immediately sent to the remote host for processing.
268 In \*(Lqold line by line\*(Rq mode, all text is echoed locally,
269 and (normally) only completed lines are sent to the remote host.
270 The \*(Lqlocal echo character\*(Rq (initially \*(Lq^E\*(Rq) may be used
271 to turn off and on the local echo
272 (this would mostly be used to enter passwords
273 without the password being echoed).
277 option is enabled, or if the
281 (the default for \*(Lqold line by line\*(Rq; see below),
287 characters are trapped locally, and sent as
289 protocol sequences to the remote side.
292 has ever been enabled, then the user's
305 There are options (see
312 which cause this action to flush subsequent output to the terminal
313 (until the remote host acknowledges the
315 sequence) and flush previous terminal input
321 While connected to a remote host,
323 command mode may be entered by typing the
325 \*(Lqescape character\*(Rq (initially \*(Lq^]\*(Rq).
326 When in command mode, the normal terminal editing conventions are available.
330 commands are available.
331 Only enough of each command to uniquely identify it need be typed
332 (this is also true for arguments to the
343 .Bl -tag -width "mode type"
344 .It Ic auth Ar argument ...
345 The auth command manipulates the information sent through the
346 .Dv TELNET AUTHENTICATE
347 option. Valid arguments for the
350 .Bl -tag -width "disable type"
351 .It Ic disable Ar type
352 Disables the specified type of authentication. To
353 obtain a list of available types, use the
356 .It Ic enable Ar type
357 Enables the specified type of authentication. To
358 obtain a list of available types, use the
362 Lists the current status of the various types of
368 session and return to command mode.
369 .It Ic display Ar argument ...
370 Displays all, or some, of the
375 .It Ic encrypt Ar argument ...
376 The encrypt command manipulates the information sent through the
380 Valid arguments for the
384 .It Ic disable Ar type Xo
385 .Op Cm input | output
387 Disables the specified type of encryption. If you
388 omit the input and output, both input and output
389 are disabled. To obtain a list of available
391 .Ic encrypt disable ?\&
393 .It Ic enable Ar type Xo
394 .Op Cm input | output
396 Enables the specified type of encryption. If you
397 omit input and output, both input and output are
398 enabled. To obtain a list of available types, use the
399 .Ic encrypt enable ?\&
402 This is the same as the
403 .Ic encrypt start input
406 This is the same as the
407 .Ic encrypt stop input
410 This is the same as the
411 .Ic encrypt start output
414 This is the same as the
415 .Ic encrypt stop output
417 .It Ic start Op Cm input | output
418 Attempts to start encryption. If you omit
422 both input and output are enabled. To
423 obtain a list of available types, use the
424 .Ic encrypt enable ?\&
427 Lists the current status of encryption.
428 .It Ic stop Op Cm input | output
429 Stops encryption. If you omit input and output,
430 encryption is on both input and output.
432 Sets the default type of encryption to be used
439 .It Ic environ Ar arguments ...
442 command is used to manipulate the
443 variables that may be sent through the
446 The initial set of variables is taken from the users
447 environment, with only the
451 variables being exported by default.
454 variable is also exported if the
460 Valid arguments for the
464 .It Ic define Ar variable value
469 Any variables defined by this command are automatically exported.
472 may be enclosed in single or double quotes so
473 that tabs and spaces may be included.
474 .It Ic undefine Ar variable
477 from the list of environment variables.
478 .It Ic export Ar variable
481 to be exported to the remote side.
482 .It Ic unexport Ar variable
485 to not be exported unless
486 explicitly asked for by the remote side.
488 List the current set of environment variables.
491 will be sent automatically,
492 other variables will only be sent if explicitly requested.
494 Prints out help information for the
501 option to the remote side.
502 This command is similar to a
504 command; however, if the remote side does not support the
506 option, nothing happens.
507 If, however, the remote side does support the
509 option, this command should cause the remote side to close the
512 If the remote side also supports the concept of
513 suspending a user's session for later reattachment,
514 the logout argument indicates that you
515 should terminate the session immediately.
518 is one of several options, depending on the state of the
521 The remote host is asked for permission to go into the requested mode.
522 If the remote host is capable of entering that mode, the requested
523 mode will be entered.
528 option, or, if the remote side does not understand the
530 option, then enter \*(Lqcharacter at a time\*(Rq mode.
534 option, or, if the remote side does not understand the
536 option, then attempt to enter \*(Lqold-line-by-line\*(Rq mode.
537 .It Ic isig Pq Ic \-isig
538 Attempt to enable (disable) the
543 This requires that the
546 .It Ic edit Pq Ic \-edit
547 Attempt to enable (disable) the
552 This requires that the
555 .It Ic softtabs Pq Ic \-softtabs
556 Attempt to enable (disable) the
561 This requires that the
564 .It Ic litecho Pq Ic \-litecho
565 Attempt to enable (disable) the
570 This requires that the
574 Prints out help information for the
581 .Op Oo Fl Oc Ns Ar port
583 Open a connection to the named host.
587 will attempt to contact a
589 server at the default port.
590 The host specification may be either a host name (see
592 an Internet address specified in the \*(Lqdot notation\*(Rq (see
594 or IPv6 host name or IPv6 coloned-hexadecimal address.
597 option may be used to specify the user name
598 to be passed to the remote system via the
601 When connecting to a non-standard port,
603 omits any automatic initiation of
605 options. When the port number is preceded by a minus sign,
606 the initial option negotiation is done.
607 After establishing a connection, the file
610 users home directory is opened. Lines beginning with a # are
611 comment lines. Blank lines are ignored. Lines that begin
612 without white space are the start of a machine entry. The
613 first thing on the line is the name of the machine that is
614 being connected to. The rest of the line, and successive
615 lines that begin with white space are assumed to be
617 commands and are processed as if they had been typed
626 An end of file (in command mode) will also close a session and exit.
627 .It Ic send Ar arguments
628 Sends one or more special character sequences to the remote host.
629 The following are the arguments which may be specified
630 (more than one argument may be specified at a time):
631 .Bl -tag -width escape
641 (Abort Output) sequence, which should cause the remote system to flush
651 sequence, to which the remote system may or may not choose to respond.
655 (Break) sequence, which may have significance to the remote
661 sequence, which should cause the remote system to erase the last character
667 sequence, which should cause the remote system to erase the line currently
682 escape character (initially \*(Lq^\*(Rq).
687 sequence, which likely has no significance to the remote system.
689 If the remote side supports the
693 will send the subnegotiation to request that the server send
694 its current option status.
698 (Interrupt Process) sequence, which should cause the remote
699 system to abort the currently running process.
714 This sequence causes the remote system to discard all previously typed
715 (but not yet read) input.
716 This sequence is sent as
719 data (and may not work if the remote system is a
722 it doesn't work, a lower case \*(Lqr\*(Rq may be echoed on the terminal).
732 can be either a decimal number between 0 and 255,
733 or a symbolic name for a specific
741 to print out help information, including
742 a list of known symbolic names.
744 Prints out help information for the
748 .It Ic set Ar argument value
749 .It Ic unset Ar argument value
752 command will set any one of a number of
754 variables to a specific value or to
758 turns off the function associated with
759 the variable, this is equivalent to using the
764 command will disable or set to
766 any of the specified functions.
767 The values of variables may be interrogated with the
770 The variables which may be set or unset, but not toggled, are
771 listed here. In addition, any of the variables for the
773 command may be explicitly set or unset using
779 .Bl -tag -width escape
783 is in localchars mode, or
785 is enabled, and the status character is typed, a
789 preceding) is sent to the
790 remote host. The initial value for the \*(LqAre You There\*(Rq
791 character is the terminal's status character.
793 This is the value (initially \*(Lq^E\*(Rq) which, when in
794 \*(Lqline by line\*(Rq mode, toggles between doing local echoing
795 of entered characters (for normal processing), and suppressing
796 echoing of entered characters (for entering, say, a password).
802 or \*(Lqold line by line\*(Rq mode, entering this character
803 as the first character on a line will cause this character to be
804 sent to the remote system.
805 The initial value of the eof character is taken to be the terminal's
820 is operating in \*(Lqcharacter at a time\*(Rq mode, then when this
821 character is typed, a
827 is sent to the remote system.
828 The initial value for the erase character is taken to be
835 escape character (initially \*(Lq^[\*(Rq) which causes entry
838 command mode (when connected to a remote system).
850 character is typed, a
856 is sent to the remote host.
857 The initial value for the flush character is taken to be
868 characters that, when typed, cause partial lines to be
869 forwarded to the remote system. The initial value for
870 the forwarding characters are taken from the terminal's
871 eol and eol2 characters.
883 character is typed, a
889 is sent to the remote host.
890 The initial value for the interrupt character is taken to be
906 is operating in \*(Lqcharacter at a time\*(Rq mode, then when this
907 character is typed, a
913 is sent to the remote system.
914 The initial value for the kill character is taken to be
923 or \*(Lqold line by line\*(Rq mode, then this character is taken to
927 The initial value for the lnext character is taken to be
942 character is typed, a
948 is sent to the remote host.
949 The initial value for the quit character is taken to be
958 or \*(Lqold line by line\*(Rq mode, then this character is taken to
962 The initial value for the reprint character is taken to be
967 This is the rlogin escape character.
970 escape character is ignored unless it is
971 preceded by this character at the beginning of a line.
972 This character, at the beginning of a line followed by
973 a "." closes the connection; when followed by a ^Z it
976 command. The initial state is to
982 .Dv TELNET TOGGLE-FLOW-CONTROL
983 option has been enabled,
984 then this character is taken to
988 The initial value for the start character is taken to be
994 .Dv TELNET TOGGLE-FLOW-CONTROL
995 option has been enabled,
996 then this character is taken to
1000 The initial value for the stop character is taken to be
1013 character is typed, a
1019 is sent to the remote host.
1020 The initial value for the suspend character is taken to be
1025 This is the file to which the output, caused by
1031 will be written. If it is set to
1033 then tracing information will be written to standard output (the default).
1039 or \*(Lqold line by line\*(Rq mode, then this character is taken to
1043 The initial value for the worderase character is taken to be
1053 .It Ic opie Ar sequence challenge
1056 command computes a response to the OPIE challenge.
1060 command (Set Local Characters) is used to set
1061 or change the state of the special
1065 been enabled. Special characters are characters that get
1068 commands sequences (like
1072 or line editing characters (like
1076 By default, the local special characters are exported.
1079 Verify the current settings for the current special characters.
1080 The remote side is requested to send all the current special
1081 character settings, and if there are any discrepancies with
1082 the local side, the local side will switch to the remote value.
1084 Switch to the local defaults for the special characters. The
1085 local default characters are those of the local terminal at
1090 Switch to the remote defaults for the special characters.
1091 The remote default characters are those of the remote system
1092 at the time when the
1094 connection was established.
1096 Prints out help information for the
1101 Show the current status of
1103 This includes the peer one is connected to, as well
1104 as the current mode.
1105 .It Ic toggle Ar arguments ...
1110 various flags that control how
1113 These flags may be set explicitly to
1121 commands listed above.
1122 More than one argument may be specified.
1123 The state of these flags may be interrogated with the
1126 Valid arguments are:
1129 Turns on debugging information for the authentication code.
1141 characters are recognized (and transformed into
1147 refuses to display any data on the user's terminal
1148 until the remote system acknowledges (via a
1149 .Dv TELNET TIMING MARK
1151 that it has processed those
1154 The initial value for this toggle is
1156 if the terminal user had not
1157 done an "stty noflsh", otherwise
1164 option is negotiated, by
1165 default the actual encryption (decryption) of the data
1166 stream does not start automatically. The autoencrypt
1167 (autodecrypt) command states that encryption of the
1168 output (input) stream should be enabled as soon as
1171 If the remote side supports the
1172 .Dv TELNET AUTHENTICATION
1175 attempts to use it to perform automatic authentication. If the
1177 option is not supported, the user's login
1178 name are propagated through the
1181 This command is the same as specifying
1193 then when either the
1197 characters is typed (see
1199 above for descriptions of the
1203 characters), the resulting
1205 sequence sent is followed by the
1210 cause the remote system to begin throwing away all previously
1211 typed input until both of the
1213 sequences have been read and acted upon.
1214 The initial value of this toggle is
1217 Enable or disable the
1219 option on both input and output.
1221 Enable or disable the
1225 Enable or disable the
1231 then carriage returns will be sent as
1235 then carriage returns will be send as
1237 The initial value for this toggle is
1240 Toggle carriage return mode.
1241 When this mode is enabled, most carriage return characters received from
1242 the remote host will be mapped into a carriage return followed by
1244 This mode does not affect those characters typed by the user, only
1245 those received from the remote host.
1246 This mode is not very useful unless the remote host
1247 only sends carriage return, but never line feed.
1248 The initial value for this toggle is
1251 Toggles socket level debugging (useful only to the
1253 The initial value for this toggle is
1256 Turns on debugging information for the encryption code.
1269 above) are recognized locally, and transformed into (hopefully) appropriate
1282 The initial value for this toggle is
1284 in \*(Lqold line by line\*(Rq mode,
1287 in \*(Lqcharacter at a time\*(Rq mode.
1290 option is enabled, the value of
1292 is ignored, and assumed to always be
1296 has ever been enabled, then
1312 Toggles the display of all network data (in hexadecimal format).
1313 The initial value for this toggle is
1316 Toggles the display of some internal
1318 protocol processing (having to do with
1321 The initial value for this toggle is
1326 toggle is enabled, if
1328 is enabled the output from the
1330 command will be formatted in a more user readable format.
1331 Spaces are put between each character in the output, and the
1334 escape sequence is preceded by a '*' to aid in locating them.
1336 When the skiprc toggle is
1339 skips the reading of the
1341 file in the users home
1342 directory when connections are opened. The initial
1343 value for this toggle is
1346 Toggles the display of all terminal data (in hexadecimal format).
1347 The initial value for this toggle is
1349 .It Ic verbose_encrypt
1355 prints out a message each time encryption is enabled or
1356 disabled. The initial value for this toggle is
1366 This command only works when the user is using the
1368 .It Ic \&! Op Ar command
1369 Execute a single command in a subshell on the local
1372 is omitted, then an interactive
1373 subshell is invoked.
1374 .It Ic ?\& Op Ar command
1375 Get help. With no arguments,
1377 prints a help summary.
1382 will print the help information for just that command.
1387 utility uses at least the
1393 environment variables.
1394 Other environment variables may be propagated
1395 to the other side via the
1399 .Bl -tag -width ~/.telnetrc -compact
1401 user customized telnet startup values
1415 IPv6 support was added by WIDE/KAME project.
1417 On some remote systems, echo has to be turned off manually when in
1418 \*(Lqold line by line\*(Rq mode.
1420 In \*(Lqold line by line\*(Rq mode or
1424 character is only recognized (and sent to the remote system)
1425 when it is the first character on a line.