1TELNET(1) BSD General Commands Manual TELNET(1)
2
4 telnet — user interface to the TELNET protocol
5
7 telnet [-468EFKLacdfrx] [-X authtype] [-b hostalias] [-e escapechar]
8 [-k realm] [-l user] [-n tracefile] [host [port]]
9
11 The telnet command is used to communicate with another host using the
12 TELNET protocol. If telnet is invoked without the host argument, it
13 enters command mode, indicated by its prompt (telnet>). In this mode, it
14 accepts and executes the commands listed below. If it is invoked with
15 arguments, it performs an open command with those arguments.
16 If a hostname is resolved to multiple IP addresses, telnet attempts to
18 establish a connection with each address until one of them is successful
19 or until no more addresses are left.
20 The options are as follows:
22 -4 Force IPv4 address resolution.
24 -6 Force IPv6 address resolution.
26 -7 Strip 8th bit on input and output. Telnet is 8-bit clean by
28 default but doesn't send the TELNET BINARY option unless forced.
29 -8 Specifies an 8-bit data path. This causes an attempt to negoti‐
31 ate the TELNET BINARY option on both input and output.
32 -E Stops any character from being recognized as an escape character.
34 -F If Kerberos V5 authentication is being used, the -F option allows
36 the local credentials to be forwarded to the remote system,
37 including any credentials that have already been forwarded into
38 the local environment.
39 -K Specifies no automatic login to the remote system.
41 -L Specifies an 8-bit data path on output. This causes the BINARY
43 option to be negotiated on output.
44 -X atype
46 Disables the atype type of authentication.
47 -a Attempt automatic login. Currently, this sends the user name via
49 the USER variable of the ENVIRON option if supported by the
50 remote system. The name used is that of the current user as
51 returned by getlogin(2) if it agrees with the current user ID,
52 otherwise it is the name associated with the user ID.
53 -b hostalias
55 Uses bind(2) on the local socket to bind it to an aliased address
56 (see ifconfig(8) and the ``alias'' specifier) or to the address
57 of another interface than the one naturally chosen by connect(2).
58 This can be useful when connecting to services which use IP
59 addresses for authentication and reconfiguration of the server is
60 undesirable (or impossible).
61 -c Disables the reading of the user's .telnetrc file. (See the
63 toggle skiprc command on this man page.)
64 -d Sets the initial value of the debug toggle to TRUE.
66 -e escapechar
68 Sets the initial telnet escape character to escapechar. If
69 escapechar is omitted, then there will be no escape character.
70 -f If Kerberos V5 authentication is being used, the -f option allows
72 the local credentials to be forwarded to the remote system.
73 -k realm
75 If Kerberos authentication is being used, the -k option requests
76 that telnet obtain tickets for the remote host in realm realm
77 instead of the remote host's realm, as determined by
78 krb_realmofhost(3).
79 -l user
81 When connecting to the remote system, if the remote system under‐
82 stands the ENVIRON option, then user will be sent to the remote
83 system as the value for the variable USER. This option implies
84 the -a option. This option may also be used with the open com‐
85 mand.
86 -n tracefile
88 Opens tracefile for recording trace information. See the set
89 tracefile command below.
90 -r Specifies a user interface similar to rlogin(1). In this mode,
92 the escape character is set to the tilde (~) character, unless
93 modified by the -e option.
94 -x Turns on encryption of the data stream if possible.
96 host Indicates the official name, an alias, or the Internet address of
98 a remote host.
99 port Indicates a port number (address of an application). If a number
101 is not specified, the default telnet port is used.
102 When in rlogin mode, a line of the form ~. disconnects from the remote
104 host; ~ is the telnet escape character. Similarly, the line ~^Z suspends
105 the telnet session. The line ~^] escapes to the normal telnet escape
106 prompt.
107 Once a connection has been opened, telnet will attempt to enable the
109 TELNET LINEMODE option. If this fails, telnet will revert to one of two
110 input modes: either ``character at a time'' or ``old line by line''
111 depending on what the remote system supports.
112 When LINEMODE is enabled, character processing is done on the local sys‐
114 tem, under the control of the remote system. When input editing or char‐
115 acter echoing is to be disabled, the remote system will relay that infor‐
116 mation. The remote system will also relay changes to any special charac‐
117 ters that happen on the remote system, so that they can take effect on
118 the local system.
119 In ``character at a time'' mode, most text typed is immediately sent to
121 the remote host for processing.
122 In ``old line by line'' mode, all text is echoed locally, and (normally)
124 only completed lines are sent to the remote host. The ``local echo char‐
125 acter'' (initially ``^E'') may be used to turn off and on the local echo
126 (this would mostly be used to enter passwords without the password being
127 echoed).
128 If the LINEMODE option is enabled, or if the localchars toggle is TRUE
130 (the default for ``old line by line''; see below), the user's quit, intr,
131 and flush characters are trapped locally, and sent as TELNET protocol
132 sequences to the remote side. If LINEMODE has ever been enabled, then
133 the user's susp and eof are also sent as TELNET protocol sequences, and
134 quit is sent as a TELNET ABORT instead of BREAK. There are options (see
135 toggle autoflush and toggle autosynch below) which cause this action to
136 flush subsequent output to the terminal (until the remote host acknowl‐
137 edges the TELNET sequence) and flush previous terminal input (in the case
138 of quit and intr).
139 While connected to a remote host, telnet command mode may be entered by
141 typing the telnet ``escape character'' (initially ``^]''). When in com‐
142 mand mode, the normal terminal editing conventions are available. Note
143 that the escape character will return to the command mode of the initial
144 invocation of telnet that has the controlling terminal. Use the send
145 escape command to switch to command mode in subsequent telnet processes
146 on remote hosts.
147 The following telnet commands are available. Only enough of each command
149 to uniquely identify it need be typed (this is also true for arguments to
150 the mode, set, toggle, unset, slc, environ, and display commands).
151 auth argument [...]
153 The auth command manipulates the information sent through the
154 TELNET AUTHENTICATE option. Valid arguments for the auth com‐
155 mand are as follows:
156 disable type Disables the specified type of authentication.
158 To obtain a list of available types, use the
159 auth disable ? command.
160 enable type Enables the specified type of authentication.
162 To obtain a list of available types, use the
163 auth enable ? command.
164 status Lists the current status of the various types of
166 authentication.
167 close Close a TELNET session and return to command mode.
169 display argument [...]
171 Displays all, or some, of the set and toggle values (see
172 below).
173 encrypt argument [...]
175 The encrypt command manipulates the information sent through
176 the TELNET ENCRYPT option.
177 Valid arguments for the encrypt command are as follows:
179 disable type [input|output]
181 Disables the specified type of encryption. If
182 you omit input and output, both input and output
183 are disabled. To obtain a list of available
184 types, use the encrypt disable ? command.
185 enable type [input|output]
187 Enables the specified type of encryption. If
188 you omit input and output, both input and output
189 are enabled. To obtain a list of available
190 types, use the encrypt enable ? command.
191 input This is the same as the encrypt start input com‐
193 mand.
194 -input This is the same as the encrypt stop input com‐
196 mand.
197 output This is the same as the encrypt start output
199 command.
200 -output This is the same as the encrypt stop output com‐
202 mand.
203 start [input|output]
205 Attempts to start encryption. If you omit input
206 and output, both input and output are enabled.
207 To obtain a list of available types, use the
208 encrypt enable ? command.
209 status Lists the current status of encryption.
211 stop [input|output]
213 Stops encryption. If you omit input and output,
214 encryption is on both input and output.
215 type type Sets the default type of encryption to be used
217 with later encrypt start or encrypt stop com‐
218 mands.
219 environ arguments [...]
221 The environ command is used to manipulate the variables that
222 may be sent through the TELNET ENVIRON option. The initial
223 set of variables is taken from the users environment, with
224 only the DISPLAY and PRINTER variables being exported by
225 default. The USER variable is also exported if the -a or -l
226 options are used.
227 Valid arguments for the environ command are:
228 define variable value
230 Define the variable variable to have a value of
231 value. Any variables defined by this command are
232 automatically exported. The value may be enclosed
233 in single or double quotes so that tabs and spaces
234 may be included.
235 undefine variable
237 Remove variable from the list of environment vari‐
238 ables.
239 export variable
241 Mark the variable variable to be exported to the
242 remote side.
243 unexport variable
245 Mark the variable variable to not be exported
246 unless explicitly asked for by the remote side.
247 list List the current set of environment variables.
249 Those marked with a * will be sent automatically,
250 other variables will only be sent if explicitly
251 requested.
252 ? Prints out help information for the environ com‐
254 mand.
255 logout Sends the TELNET LOGOUT option to the remote side. This com‐
257 mand is similar to a close command; however, if the remote
258 side does not support the LOGOUT option, nothing happens. If,
259 however, the remote side does support the LOGOUT option, this
260 command should cause the remote side to close the TELNET con‐
261 nection. If the remote side also supports the concept of sus‐
262 pending a user's session for later reattachment, the logout
263 argument indicates that you should terminate the session imme‐
264 diately.
265 mode type type is one of several options, depending on the state of the
267 TELNET session. The remote host is asked for permission to go
268 into the requested mode. If the remote host is capable of
269 entering that mode, the requested mode will be entered.
270 character Disable the TELNET LINEMODE option, or, if the
272 remote side does not understand the LINEMODE
273 option, then enter ``character at a time'' mode.
274 line Enable the TELNET LINEMODE option, or, if the
276 remote side does not understand the LINEMODE
277 option, then attempt to enter ``old-line-by-
278 line'' mode.
279 isig (-isig) Attempt to enable (disable) the TRAPSIG mode of
281 the LINEMODE option. This requires that the
282 LINEMODE option be enabled.
283 edit (-edit) Attempt to enable (disable) the EDIT mode of the
285 LINEMODE option. This requires that the
286 LINEMODE option be enabled.
287 softtabs (-softtabs)
289 Attempt to enable (disable) the SOFT_TAB mode of
290 the LINEMODE option. This requires that the
291 LINEMODE option be enabled.
292 litecho (-litecho)
294 Attempt to enable (disable) the LIT_ECHO mode of
295 the LINEMODE option. This requires that the
296 LINEMODE option be enabled.
297 ? Prints out help information for the mode com‐
299 mand.
300 open host [-l user] [[-] port]
302 Open a connection to the named host. If no port number is
303 specified, telnet will attempt to contact a TELNET server at
304 the default port. The host specification may be either a host
305 name (see hosts(5)) or an Internet address specified in the
306 ``dot notation'' (see inet(3)). The -l option may be used to
307 specify the user name to be passed to the remote system via
308 the ENVIRON option. When connecting to a non-standard port,
309 telnet omits any automatic initiation of TELNET options. When
310 the port number is preceded by a minus sign, the initial
311 option negotiation is done. After establishing a connection,
312 the file .telnetrc in the user's home directory is opened.
313 Lines beginning with a ``#'' are comment lines. Blank lines
314 are ignored. Lines that begin without whitespace are the
315 start of a machine entry. The first thing on the line is the
316 name of the machine that is being connected to. The rest of
317 the line, and successive lines that begin with whitespace are
318 assumed to be telnet commands and are processed as if they had
319 been typed in manually to the telnet command prompt.
320 quit Close any open TELNET session and exit telnet. An end-of-file
322 (in command mode) will also close a session and exit.
323 send arguments
325 Sends one or more special character sequences to the remote
326 host. The following are the arguments which may be specified
327 (more than one argument may be specified at a time):
328 abort Sends the TELNET ABORT (Abort processes) sequence.
330 ao Sends the TELNET AO (Abort Output) sequence, which
332 should cause the remote system to flush all output
333 from the remote system to the user's terminal.
334 ayt Sends the TELNET AYT (Are You There) sequence, to
336 which the remote system may or may not choose to
337 respond.
338 brk Sends the TELNET BRK (Break) sequence, which may have
340 significance to the remote system.
341 ec Sends the TELNET EC (Erase Character) sequence, which
343 should cause the remote system to erase the last char‐
344 acter entered.
345 el Sends the TELNET EL (Erase Line) sequence, which
347 should cause the remote system to erase the line cur‐
348 rently being entered.
349 eof Sends the TELNET EOF (End Of File) sequence.
351 eor Sends the TELNET EOR (End of Record) sequence.
353 escape Sends the current telnet escape character (initially
355 ``^]'').
356 ga Sends the TELNET GA (Go Ahead) sequence, which likely
358 has no significance to the remote system.
359 getstatus
361 If the remote side supports the TELNET STATUS command,
362 getstatus will send the subnegotiation to request that
363 the server send its current option status.
364 ip Sends the TELNET IP (Interrupt Process) sequence,
366 which should cause the remote system to abort the cur‐
367 rently running process.
368 nop Sends the TELNET NOP (No OPeration) sequence.
370 susp Sends the TELNET SUSP (SUSPend process) sequence.
372 synch Sends the TELNET SYNCH sequence. This sequence causes
374 the remote system to discard all previously typed (but
375 not yet read) input. This sequence is sent as TCP
376 urgent data (and may not work if the remote system is
377 a 4.2BSD system -- if it doesn't work, a lower case
378 ``r'' may be echoed on the terminal).
379 do cmd Sends the TELNET DO cmd sequence. cmd can be either a
381 decimal number between 0 and 255, or a symbolic name
382 for a specific TELNET command. cmd can also be either
383 help or ? to print out help information, including a
384 list of known symbolic names.
385 dont cmd
387 Sends the TELNET DONT cmd sequence. cmd can be either
388 a decimal number between 0 and 255, or a symbolic name
389 for a specific TELNET command. cmd can also be either
390 help or ? to print out help information, including a
391 list of known symbolic names.
392 will cmd
394 Sends the TELNET WILL cmd sequence. cmd can be either
395 a decimal number between 0 and 255, or a symbolic name
396 for a specific TELNET command. cmd can also be either
397 help or ? to print out help information, including a
398 list of known symbolic names.
399 wont cmd
401 Sends the TELNET WONT cmd sequence. cmd can be either
402 a decimal number between 0 and 255, or a symbolic name
403 for a specific TELNET command. cmd can also be either
404 help or ? to print out help information, including a
405 list of known symbolic names.
406 ? Prints out help information for the send command.
408 set argument value
410 unset argument value
412 The set command will set any one of a number of telnet vari‐
413 ables to a specific value or to TRUE. The special value off
414 turns off the function associated with the variable; this is
415 equivalent to using the unset command. The unset command will
416 disable or set to FALSE any of the specified functions. The
417 values of variables may be interrogated with the display com‐
418 mand. The variables which may be set or unset, but not tog‐
419 gled, are listed here. In addition, any of the variables for
420 the toggle command may be explicitly set or unset using the
421 set and unset commands.
422 ayt If TELNET is in localchars mode, or LINEMODE is
424 enabled, and the status character is typed, a TELNET
425 AYT sequence (see send ayt preceding) is sent to the
426 remote host. The initial value for the "Are You
427 There" character is the terminal's status character.
428 echo This is the value (initially ``^E'') which, when in
430 ``line by line'' mode, toggles between doing local
431 echoing of entered characters (for normal processing),
432 and suppressing echoing of entered characters (for
433 entering, say, a password).
434 eof If telnet is operating in LINEMODE or ``old line by
436 line'' mode, entering this character as the first
437 character on a line will cause this character to be
438 sent to the remote system. The initial value of the
439 eof character is taken to be the terminal's eof char‐
440 acter.
441 erase If telnet is in localchars mode (see toggle localchars
443 below), and if telnet is operating in ``character at a
444 time'' mode, then when this character is typed, a
445 TELNET EC sequence (see send ec above) is sent to the
446 remote system. The initial value for the erase char‐
447 acter is taken to be the terminal's erase character.
448 escape This is the telnet escape character (initially ``^['')
450 which causes entry into telnet command mode (when con‐
451 nected to a remote system).
452 flushoutput
454 If telnet is in localchars mode (see toggle localchars
455 below) and the flushoutput character is typed, a
456 TELNET AO sequence (see send ao above) is sent to the
457 remote host. The initial value for the flush charac‐
458 ter is taken to be the terminal's flush character.
459 forw1
461 forw2 If TELNET is operating in LINEMODE, these are the
463 characters that, when typed, cause partial lines to be
464 forwarded to the remote system. The initial value for
465 the forwarding characters are taken from the termi‐
466 nal's eol and eol2 characters.
467 interrupt
469 If telnet is in localchars mode (see toggle localchars
470 below) and the interrupt character is typed, a TELNET
471 IP sequence (see send ip above) is sent to the remote
472 host. The initial value for the interrupt character
473 is taken to be the terminal's intr character.
474 kill If telnet is in localchars mode (see toggle localchars
476 below), and if telnet is operating in ``character at a
477 time'' mode, then when this character is typed, a
478 TELNET EL sequence (see send el above) is sent to the
479 remote system. The initial value for the kill charac‐
480 ter is taken to be the terminal's kill character.
481 lnext If telnet is operating in LINEMODE or ``old line by
483 line'' mode, then this character is taken to be the
484 terminal's lnext character. The initial value for the
485 lnext character is taken to be the terminal's lnext
486 character.
487 quit If telnet is in localchars mode (see toggle localchars
489 below) and the quit character is typed, a TELNET BRK
490 sequence (see send brk above) is sent to the remote
491 host. The initial value for the quit character is
492 taken to be the terminal's quit character.
493 reprint
495 If telnet is operating in LINEMODE or old line by
496 line'' mode, then this character is taken to be the
497 terminal's reprint character. The initial value for
498 the reprint character is taken to be the terminal's
499 reprint character.
500 rlogin This is the rlogin escape character. If set, the nor‐
502 mal TELNET escape character is ignored unless it is
503 preceded by this character at the beginning of a line.
504 This character, at the beginning of a line, followed
505 by a "." closes the connection; when followed by a ^Z
506 it suspends the telnet command. The initial state is
507 to disable the rlogin escape character.
508 start If the TELNET TOGGLE-FLOW-CONTROL option has been
510 enabled, then this character is taken to be the termi‐
511 nal's start character. The initial value for the
512 start character is taken to be the terminal's start
513 character.
514 stop If the TELNET TOGGLE-FLOW-CONTROL option has been
516 enabled, then this character is taken to be the termi‐
517 nal's stop character. The initial value for the stop
518 character is taken to be the terminal's stop charac‐
519 ter.
520 susp If telnet is in localchars mode, or LINEMODE is
522 enabled, and the suspend character is typed, a TELNET
523 SUSP sequence (see send susp above) is sent to the
524 remote host. The initial value for the suspend char‐
525 acter is taken to be the terminal's suspend character.
526 tracefile
528 This is the file to which the output, caused by
529 netdata or option tracing being TRUE, will be written.
530 If it is set to “-”, then tracing information will be
531 written to standard output (the default).
532 worderase
534 If telnet is operating in LINEMODE or ``old line by
535 line'' mode, then this character is taken to be the
536 terminal's worderase character. The initial value for
537 the worderase character is taken to be the terminal's
538 worderase character.
539 ? Displays the legal set (unset) commands.
541 skey sequence challenge
543 The skey command computes a response to the S/Key challenge.
544 See skey(1) for more information on the S/Key system.
545 slc state The slc command (Set Local Characters) is used to set or
547 change the state of the special characters when the TELNET
548 LINEMODE option has been enabled. Special characters are
549 characters that get mapped to TELNET commands sequences (like
550 ip or quit) or line editing characters (like erase and kill).
551 By default, the local special characters are exported.
552 check Verify the current settings for the current spe‐
554 cial characters. The remote side is requested to
555 send all the current special character settings,
556 and if there are any discrepancies with the local
557 side, the local side will switch to the remote
558 value.
559 export Switch to the local defaults for the special char‐
561 acters. The local default characters are those of
562 the local terminal at the time when telnet was
563 started.
564 import Switch to the remote defaults for the special
566 characters. The remote default characters are
567 those of the remote system at the time when the
568 TELNET connection was established.
569 ? Prints out help information for the slc command.
571 status Show the current status of telnet. This includes the peer one
573 is connected to, as well as the current mode.
574 toggle arguments [...]
576 Toggle (between TRUE and FALSE) various flags that control how
577 telnet responds to events. These flags may be set explicitly
578 to TRUE or FALSE using the set and unset commands listed
579 above. More than one argument may be specified. The state of
580 these flags may be interrogated with the display command.
581 Valid arguments are:
582 authdebug Turns on debugging information for the authenti‐
584 cation code.
585 autoflush If autoflush and localchars are both TRUE, then
587 when the ao or quit characters are recognized
588 (and transformed into TELNET sequences; see set
589 above for details), telnet refuses to display
590 any data on the user's terminal until the remote
591 system acknowledges (via a TELNET TIMING MARK
592 option) that it has processed those TELNET
593 sequences. The initial value for this toggle is
594 TRUE if the terminal user had not done an "stty
595 noflsh", otherwise FALSE (see stty(1)).
596 autodecrypt When the TELNET ENCRYPT option is negotiated, by
598 default the actual encryption (decryption) of
599 the data stream does not start automatically.
600 The autoencrypt (autodecrypt) command states
601 that encryption of the output (input) stream
602 should be enabled as soon as possible.
603 autologin If the remote side supports the TELNET
605 AUTHENTICATION option TELNET attempts to use it
606 to perform automatic authentication. If the
607 AUTHENTICATION option is not supported, the
608 user's login name are propagated through the
609 TELNET ENVIRON option. This command is the same
610 as specifying a option on the open command.
611 autosynch If autosynch and localchars are both TRUE, then
613 when either the intr or quit character is typed
614 (see set above for descriptions of the intr and
615 quit characters), the resulting TELNET sequence
616 sent is followed by the TELNET SYNCH sequence.
617 This procedure should cause the remote system to
618 begin throwing away all previously typed input
619 until both of the TELNET sequences have been
620 read and acted upon. The initial value of this
621 toggle is FALSE.
622 binary Enable or disable the TELNET BINARY option on
624 both input and output.
625 inbinary Enable or disable the TELNET BINARY option on
627 input.
628 outbinary Enable or disable the TELNET BINARY option on
630 output.
631 crlf If this is TRUE, then carriage returns will be
633 sent as <CR><LF>. If this is FALSE, then car‐
634 riage returns will be send as <CR><NUL>. The
635 initial value for this toggle is FALSE.
636 crmod Toggle carriage return mode. When this mode is
638 enabled, most carriage return characters
639 received from the remote host will be mapped
640 into a carriage return followed by a line feed.
641 This mode does not affect those characters typed
642 by the user, only those received from the remote
643 host. This mode is not very useful unless the
644 remote host only sends carriage return, but
645 never line feeds. The initial value for this
646 toggle is FALSE.
647 debug Toggles socket level debugging (useful only to
649 the superuser). The initial value for this tog‐
650 gle is FALSE.
651 encdebug Turns on debugging information for the encryp‐
653 tion code.
654 localchars If this is TRUE, then the flush, interrupt,
656 quit, erase, and kill characters (see set above)
657 are recognized locally, and transformed into
658 (hopefully) appropriate TELNET control sequences
659 (respectively ao, ip, brk, ec, and el; see send
660 above). The initial value for this toggle is
661 TRUE in ``old line by line'' mode, and FALSE in
662 ``character at a time'' mode. When the LINEMODE
663 option is enabled, the value of localchars is
664 ignored, and assumed to always be TRUE. If
665 LINEMODE has ever been enabled, then quit is
666 sent as abort, and eof and suspend are sent as
667 eof and susp (see send above).
668 netdata Toggles the display of all network data (in
670 hexadecimal format). The initial value for this
671 toggle is FALSE.
672 options Toggles the display of some internal telnet pro‐
674 tocol processing (having to do with TELNET
675 options). The initial value for this toggle is
676 FALSE.
677 prettydump When the netdata toggle is enabled, if
679 prettydump is enabled the output from the
680 netdata command will be formatted in a more user
681 readable format. Spaces are put between each
682 character in the output, and the beginning of
683 any TELNET escape sequence is preceded by a '*'
684 to aid in locating them.
685 skiprc When the skiprc toggle is TRUE, TELNET skips the
687 reading of the .telnetrc file in the user's home
688 directory when connections are opened. The ini‐
689 tial value for this toggle is FALSE.
690 termdata Toggles the display of all terminal data (in
692 hexadecimal format). The initial value for this
693 toggle is FALSE.
694 verbose_encrypt
696 When the verbose_encrypt toggle is TRUE, telnet
697 prints out a message each time encryption is
698 enabled or disabled. The initial value for this
699 toggle is FALSE.
700 ? Displays the legal toggle commands.
702 z Suspend telnet. This command only works when the user is
704 using the csh(1).
705 ! [command]
707 Execute a single command in a subshell on the local system.
708 If command is omitted, then an interactive subshell is
709 invoked.
710 ? [command]
712 Get help. With no arguments, telnet prints a help summary.
713 If a command is specified, telnet will print the help informa‐
714 tion for just that command.
715
717 telnet uses at least the HOME, SHELL, DISPLAY, and TERM environment vari‐
718 ables. Other environment variables may be propagated to the other side
719 via the TELNET ENVIRON option.
720
722 ~/.telnetrc user customized telnet startup values
723
725 The telnet command appeared in 4.2BSD.
726
728 On some remote systems, echo has to be turned off manually when in ``old
729 line by line'' mode.
730 In ``old line by line'' mode or LINEMODE the terminal's eof character is
732 only recognized (and sent to the remote system) when it is the first
733 character on a line.
734 Source routing is not supported yet for IPv6.
736BSD February 3, 1994 BSD