Annotation of src/usr.bin/telnet/telnet.1, Revision 1.1.1.1
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32: .\" from: @(#)telnet.1 8.4 (Berkeley) 2/3/94
33: .\" $Id: telnet.1,v 1.4 1994/02/25 03:00:42 cgd Exp $
34: .\"
35: .Dd February 3, 1994
36: .Dt TELNET 1
37: .Os BSD 4.2
38: .Sh NAME
39: .Nm telnet
40: .Nd user interface to the
41: .Tn TELNET
42: protocol
43: .Sh SYNOPSIS
44: .Nm telnet
45: .Op Fl 8
46: .Op Fl E
47: .Op Fl F
48: .Op Fl K
49: .Op Fl L
50: .Op Fl S Ar tos
51: .Op Fl X Ar authtype
52: .Op Fl a
53: .Op Fl c
54: .Op Fl d
55: .Op Fl e Ar escapechar
56: .Op Fl f
57: .Op Fl k Ar realm
58: .Op Fl l Ar user
59: .Op Fl n Ar tracefile
60: .Op Fl r
61: .Op Fl x
62: .Oo
63: .Ar host
64: .Op port
65: .Oc
66: .Sh DESCRIPTION
67: The
68: .Nm telnet
69: command
70: is used to communicate with another host using the
71: .Tn TELNET
72: protocol.
73: If
74: .Nm telnet
75: is invoked without the
76: .Ar host
77: argument, it enters command mode,
78: indicated by its prompt
79: .Pq Nm telnet\&> .
80: In this mode, it accepts and executes the commands listed below.
81: If it is invoked with arguments, it performs an
82: .Ic open
83: command with those arguments.
84: .Pp
85: Options:
86: .Bl -tag -width indent
87: .It Fl 8
88: Specifies an 8-bit data path. This causes an attempt to
89: negotiate the
90: .Dv TELNET BINARY
91: option on both input and output.
92: .It Fl E
93: Stops any character from being recognized as an escape character.
94: .It Fl F
95: If Kerberos V5 authentication is being used, the
96: .Fl F
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.
100: .It Fl K
101: Specifies no automatic login to the remote system.
102: .It Fl L
103: Specifies an 8-bit data path on output. This causes the
104: BINARY option to be negotiated on output.
105: .It Fl S Ar tos
106: Sets the IP type-of-service (TOS) option for the telnet
107: connection to the value
108: .Ar tos,
109: which can be a numeric TOS value
110: or, on systems that support it, a symbolic
111: TOS name found in the /etc/iptos file.
112: .It Fl X Ar atype
113: Disables the
114: .Ar atype
115: type of authentication.
116: .It Fl a
117: Attempt automatic login.
118: Currently, this sends the user name via the
119: .Ev USER
120: variable
121: of the
122: .Ev ENVIRON
123: option if supported by the remote system.
124: The name used is that of the current user as returned by
125: .Xr getlogin 2
126: if it agrees with the current user ID,
127: otherwise it is the name associated with the user ID.
128: .It Fl c
129: Disables the reading of the user's
130: .Pa \&.telnetrc
131: file. (See the
132: .Ic toggle skiprc
133: command on this man page.)
134: .It Fl d
135: Sets the initial value of the
136: .Ic debug
137: toggle to
138: .Dv TRUE
139: .It Fl e Ar escape char
140: Sets the initial
141: .Nm
142: .Nm telnet
143: escape character to
144: .Ar escape char.
145: If
146: .Ar escape char
147: is omitted, then
148: there will be no escape character.
149: .It Fl f
150: If Kerberos V5 authentication is being used, the
151: .Fl f
152: option allows the local credentials to be forwarded to the remote system.
153: .It Fl k Ar realm
154: If Kerberos authentication is being used, the
155: .Fl k
156: option requests that telnet obtain tickets for the remote host in
157: realm realm instead of the remote host's realm, as determined
158: by
159: .Xr krb_realmofhost 3 .
160: .It Fl l Ar user
161: When connecting to the remote system, if the remote system
162: understands the
163: .Ev ENVIRON
164: option, then
165: .Ar user
166: will be sent to the remote system as the value for the variable USER.
167: This option implies the
168: .Fl a
169: option.
170: This option may also be used with the
171: .Ic open
172: command.
173: .It Fl n Ar tracefile
174: Opens
175: .Ar tracefile
176: for recording trace information.
177: See the
178: .Ic set tracefile
179: command below.
180: .It Fl r
181: Specifies a user interface similar to
182: .Xr rlogin 1 .
183: In this
184: mode, the escape character is set to the tilde (~) character,
185: unless modified by the -e option.
186: .It Fl x
187: Turns on encryption of the data stream if possible. This
188: option is not available outside of the United States and
189: Canada.
190: .It Ar host
191: Indicates the official name, an alias, or the Internet address
192: of a remote host.
193: .It Ar port
194: Indicates a port number (address of an application). If a number is
195: not specified, the default
196: .Nm telnet
197: port is used.
198: .El
199: .Pp
200: When in rlogin mode, a line of the form ~. disconnects from the
201: remote host; ~ is the telnet escape character.
202: Similarly, the line ~^Z suspends the telnet session.
203: The line ~^] escapes to the normal telnet escape prompt.
204: .Pp
205: Once a connection has been opened,
206: .Nm telnet
207: will attempt to enable the
208: .Dv TELNET LINEMODE
209: option.
210: If this fails, then
211: .Nm telnet
212: will revert to one of two input modes:
213: either \*(Lqcharacter at a time\*(Rq
214: or \*(Lqold line by line\*(Rq
215: depending on what the remote system supports.
216: .Pp
217: When
218: .Dv LINEMODE
219: is enabled, character processing is done on the
220: local system, under the control of the remote system. When input
221: editing or character echoing is to be disabled, the remote system
222: will relay that information. The remote system will also relay
223: changes to any special characters that happen on the remote
224: system, so that they can take effect on the local system.
225: .Pp
226: In \*(Lqcharacter at a time\*(Rq mode, most
227: text typed is immediately sent to the remote host for processing.
228: .Pp
229: In \*(Lqold line by line\*(Rq mode, all text is echoed locally,
230: and (normally) only completed lines are sent to the remote host.
231: The \*(Lqlocal echo character\*(Rq (initially \*(Lq^E\*(Rq) may be used
232: to turn off and on the local echo
233: (this would mostly be used to enter passwords
234: without the password being echoed).
235: .Pp
236: If the
237: .Dv LINEMODE
238: option is enabled, or if the
239: .Ic localchars
240: toggle is
241: .Dv TRUE
242: (the default for \*(Lqold line by line\*(Lq; see below),
243: the user's
244: .Ic quit ,
245: .Ic intr ,
246: and
247: .Ic flush
248: characters are trapped locally, and sent as
249: .Tn TELNET
250: protocol sequences to the remote side.
251: If
252: .Dv LINEMODE
253: has ever been enabled, then the user's
254: .Ic susp
255: and
256: .Ic eof
257: are also sent as
258: .Tn TELNET
259: protocol sequences,
260: and
261: .Ic quit
262: is sent as a
263: .Dv TELNET ABORT
264: instead of
265: .Dv BREAK
266: There are options (see
267: .Ic toggle
268: .Ic autoflush
269: and
270: .Ic toggle
271: .Ic autosynch
272: below)
273: which cause this action to flush subsequent output to the terminal
274: (until the remote host acknowledges the
275: .Tn TELNET
276: sequence) and flush previous terminal input
277: (in the case of
278: .Ic quit
279: and
280: .Ic intr ) .
281: .Pp
282: While connected to a remote host,
283: .Nm telnet
284: command mode may be entered by typing the
285: .Nm telnet
286: \*(Lqescape character\*(Rq (initially \*(Lq^]\*(Rq).
287: When in command mode, the normal terminal editing conventions are available.
288: .Pp
289: The following
290: .Nm telnet
291: commands are available.
292: Only enough of each command to uniquely identify it need be typed
293: (this is also true for arguments to the
294: .Ic mode ,
295: .Ic set ,
296: .Ic toggle ,
297: .Ic unset ,
298: .Ic slc ,
299: .Ic environ ,
300: and
301: .Ic display
302: commands).
303: .Pp
304: .Bl -tag -width "mode type"
305: .It Ic auth Ar argument ...
306: The auth command manipulates the information sent through the
307: .Dv TELNET AUTHENTICATE
308: option. Valid arguments for the
309: auth command are as follows:
310: .Bl -tag -width "disable type"
311: .It Ic disable Ar type
312: Disables the specified type of authentication. To
313: obtain a list of available types, use the
314: .Ic auth disable \&?
315: command.
316: .It Ic enable Ar type
317: Enables the specified type of authentication. To
318: obtain a list of available types, use the
319: .Ic auth enable \&?
320: command.
321: .It Ic status
322: Lists the current status of the various types of
323: authentication.
324: .El
325: .It Ic close
326: Close a
327: .Tn TELNET
328: session and return to command mode.
329: .It Ic display Ar argument ...
330: Displays all, or some, of the
331: .Ic set
332: and
333: .Ic toggle
334: values (see below).
335: .It Ic encrypt Ar argument ...
336: The encrypt command manipulates the information sent through the
337: .Dv TELNET ENCRYPT
338: option.
339: .Pp
340: Note: Because of export controls, the
341: .Dv TELNET ENCRYPT
342: option is not supported outside of the United States and Canada.
343: .Pp
344: Valid arguments for the encrypt command are as follows:
345: .Bl -tag -width Ar
346: .It Ic disable Ar type Ic [input|output]
347: Disables the specified type of encryption. If you
348: omit the input and output, both input and output
349: are disabled. To obtain a list of available
350: types, use the
351: .Ic encrypt disable \&?
352: command.
353: .It Ic enable Ar type Ic [input|output]
354: Enables the specified type of encryption. If you
355: omit input and output, both input and output are
356: enabled. To obtain a list of available types, use the
357: .Ic encrypt enable \&?
358: command.
359: .It Ic input
360: This is the same as the
361: .Ic encrypt start input
362: command.
363: .It Ic -input
364: This is the same as the
365: .Ic encrypt stop input
366: command.
367: .It Ic output
368: This is the same as the
369: .Ic encrypt start output
370: command.
371: .It Ic -output
372: This is the same as the
373: .Ic encrypt stop output
374: command.
375: .It Ic start Ic [input|output]
376: Attempts to start encryption. If you omit
377: .Ic input
378: and
379: .Ic output,
380: both input and output are enabled. To
381: obtain a list of available types, use the
382: .Ic encrypt enable \&?
383: command.
384: .It Ic status
385: Lists the current status of encryption.
386: .It Ic stop Ic [input|output]
387: Stops encryption. If you omit input and output,
388: encryption is on both input and output.
389: .It Ic type Ar type
390: Sets the default type of encryption to be used
391: with later
392: .Ic encrypt start
393: or
394: .Ic encrypt stop
395: commands.
396: .El
397: .It Ic environ Ar arguments...
398: The
399: .Ic environ
400: command is used to manipulate the
401: the variables that my be sent through the
402: .Dv TELNET ENVIRON
403: option.
404: The initial set of variables is taken from the users
405: environment, with only the
406: .Ev DISPLAY
407: and
408: .Ev PRINTER
409: variables being exported by default.
410: The
411: .Ev USER
412: variable is also exported if the
413: .Fl a
414: or
415: .Fl l
416: options are used.
417: .br
418: Valid arguments for the
419: .Ic environ
420: command are:
421: .Bl -tag -width Fl
422: .It Ic define Ar variable value
423: Define the variable
424: .Ar variable
425: to have a value of
426: .Ar value.
427: Any variables defined by this command are automatically exported.
428: The
429: .Ar value
430: may be enclosed in single or double quotes so
431: that tabs and spaces may be included.
432: .It Ic undefine Ar variable
433: Remove
434: .Ar variable
435: from the list of environment variables.
436: .It Ic export Ar variable
437: Mark the variable
438: .Ar variable
439: to be exported to the remote side.
440: .It Ic unexport Ar variable
441: Mark the variable
442: .Ar variable
443: to not be exported unless
444: explicitly asked for by the remote side.
445: .It Ic list
446: List the current set of environment variables.
447: Those marked with a
448: .Cm *
449: will be sent automatically,
450: other variables will only be sent if explicitly requested.
451: .It Ic \&?
452: Prints out help information for the
453: .Ic environ
454: command.
455: .El
456: .It Ic logout
457: Sends the
458: .Dv TELNET LOGOUT
459: option to the remote side.
460: This command is similar to a
461: .Ic close
462: command; however, if the remote side does not support the
463: .Dv LOGOUT
464: option, nothing happens.
465: If, however, the remote side does support the
466: .Dv LOGOUT
467: option, this command should cause the remote side to close the
468: .Tn TELNET
469: connection.
470: If the remote side also supports the concept of
471: suspending a user's session for later reattachment,
472: the logout argument indicates that you
473: should terminate the session immediately.
474: .It Ic mode Ar type
475: .Ar Type
476: is one of several options, depending on the state of the
477: .Tn TELNET
478: session.
479: The remote host is asked for permission to go into the requested mode.
480: If the remote host is capable of entering that mode, the requested
481: mode will be entered.
482: .Bl -tag -width Ar
483: .It Ic character
484: Disable the
485: .Dv TELNET LINEMODE
486: option, or, if the remote side does not understand the
487: .Dv LINEMODE
488: option, then enter \*(Lqcharacter at a time\*(Lq mode.
489: .It Ic line
490: Enable the
491: .Dv TELNET LINEMODE
492: option, or, if the remote side does not understand the
493: .Dv LINEMODE
494: option, then attempt to enter \*(Lqold-line-by-line\*(Lq mode.
495: .It Ic isig Pq Ic \-isig
496: Attempt to enable (disable) the
497: .Dv TRAPSIG
498: mode of the
499: .Dv LINEMODE
500: option.
501: This requires that the
502: .Dv LINEMODE
503: option be enabled.
504: .It Ic edit Pq Ic \-edit
505: Attempt to enable (disable) the
506: .Dv EDIT
507: mode of the
508: .Dv LINEMODE
509: option.
510: This requires that the
511: .Dv LINEMODE
512: option be enabled.
513: .It Ic softtabs Pq Ic \-softtabs
514: Attempt to enable (disable) the
515: .Dv SOFT_TAB
516: mode of the
517: .Dv LINEMODE
518: option.
519: This requires that the
520: .Dv LINEMODE
521: option be enabled.
522: .It Ic litecho Pq Ic \-litecho
523: Attempt to enable (disable) the
524: .Dv LIT_ECHO
525: mode of the
526: .Dv LINEMODE
527: option.
528: This requires that the
529: .Dv LINEMODE
530: option be enabled.
531: .It Ic \&?
532: Prints out help information for the
533: .Ic mode
534: command.
535: .El
536: .It Xo
537: .Ic open Ar host
538: .Oo Op Fl l
539: .Ar user
540: .Oc Ns Oo Fl
541: .Ar port Oc
542: .Xc
543: Open a connection to the named host.
544: If no port number
545: is specified,
546: .Nm telnet
547: will attempt to contact a
548: .Tn TELNET
549: server at the default port.
550: The host specification may be either a host name (see
551: .Xr hosts 5 )
552: or an Internet address specified in the \*(Lqdot notation\*(Rq (see
553: .Xr inet 3 ) .
554: The
555: .Op Fl l
556: option may be used to specify the user name
557: to be passed to the remote system via the
558: .Ev ENVIRON
559: option.
560: When connecting to a non-standard port,
561: .Nm telnet
562: omits any automatic initiation of
563: .Tn TELNET
564: options. When the port number is preceded by a minus sign,
565: the initial option negotiation is done.
566: After establishing a connection, the file
567: .Pa \&.telnetrc
568: in the
569: users home directory is opened. Lines beginning with a # are
570: comment lines. Blank lines are ignored. Lines that begin
571: without white space are the start of a machine entry. The
572: first thing on the line is the name of the machine that is
573: being connected to. The rest of the line, and successive
574: lines that begin with white space are assumed to be
575: .Nm telnet
576: commands and are processed as if they had been typed
577: in manually to the
578: .Nm telnet
579: command prompt.
580: .It Ic quit
581: Close any open
582: .Tn TELNET
583: session and exit
584: .Nm telnet .
585: An end of file (in command mode) will also close a session and exit.
586: .It Ic send Ar arguments
587: Sends one or more special character sequences to the remote host.
588: The following are the arguments which may be specified
589: (more than one argument may be specified at a time):
590: .Pp
591: .Bl -tag -width escape
592: .It Ic abort
593: Sends the
594: .Dv TELNET ABORT
595: (Abort
596: processes)
597: sequence.
598: .It Ic ao
599: Sends the
600: .Dv TELNET AO
601: (Abort Output) sequence, which should cause the remote system to flush
602: all output
603: .Em from
604: the remote system
605: .Em to
606: the user's terminal.
607: .It Ic ayt
608: Sends the
609: .Dv TELNET AYT
610: (Are You There)
611: sequence, to which the remote system may or may not choose to respond.
612: .It Ic brk
613: Sends the
614: .Dv TELNET BRK
615: (Break) sequence, which may have significance to the remote
616: system.
617: .It Ic ec
618: Sends the
619: .Dv TELNET EC
620: (Erase Character)
621: sequence, which should cause the remote system to erase the last character
622: entered.
623: .It Ic el
624: Sends the
625: .Dv TELNET EL
626: (Erase Line)
627: sequence, which should cause the remote system to erase the line currently
628: being entered.
629: .It Ic eof
630: Sends the
631: .Dv TELNET EOF
632: (End Of File)
633: sequence.
634: .It Ic eor
635: Sends the
636: .Dv TELNET EOR
637: (End of Record)
638: sequence.
639: .It Ic escape
640: Sends the current
641: .Nm telnet
642: escape character (initially \*(Lq^\*(Rq).
643: .It Ic ga
644: Sends the
645: .Dv TELNET GA
646: (Go Ahead)
647: sequence, which likely has no significance to the remote system.
648: .It Ic getstatus
649: If the remote side supports the
650: .Dv TELNET STATUS
651: command,
652: .Ic getstatus
653: will send the subnegotiation to request that the server send
654: its current option status.
655: .It Ic ip
656: Sends the
657: .Dv TELNET IP
658: (Interrupt Process) sequence, which should cause the remote
659: system to abort the currently running process.
660: .It Ic nop
661: Sends the
662: .Dv TELNET NOP
663: (No OPeration)
664: sequence.
665: .It Ic susp
666: Sends the
667: .Dv TELNET SUSP
668: (SUSPend process)
669: sequence.
670: .It Ic synch
671: Sends the
672: .Dv TELNET SYNCH
673: sequence.
674: This sequence causes the remote system to discard all previously typed
675: (but not yet read) input.
676: This sequence is sent as
677: .Tn TCP
678: urgent
679: data (and may not work if the remote system is a
680: .Bx 4.2
681: system -- if
682: it doesn't work, a lower case \*(Lqr\*(Rq may be echoed on the terminal).
683: .It Ic do Ar cmd
684: .It Ic dont Ar cmd
685: .It Ic will Ar cmd
686: .It Ic wont Ar cmd
687: Sends the
688: .Dv TELNET DO
689: .Ar cmd
690: sequence.
691: .Ar Cmd
692: can be either a decimal number between 0 and 255,
693: or a symbolic name for a specific
694: .Dv TELNET
695: command.
696: .Ar Cmd
697: can also be either
698: .Ic help
699: or
700: .Ic \&?
701: to print out help information, including
702: a list of known symbolic names.
703: .It Ic \&?
704: Prints out help information for the
705: .Ic send
706: command.
707: .El
708: .It Ic set Ar argument value
709: .It Ic unset Ar argument value
710: The
711: .Ic set
712: command will set any one of a number of
713: .Nm telnet
714: variables to a specific value or to
715: .Dv TRUE .
716: The special value
717: .Ic off
718: turns off the function associated with
719: the variable, this is equivalent to using the
720: .Ic unset
721: command.
722: The
723: .Ic unset
724: command will disable or set to
725: .Dv FALSE
726: any of the specified functions.
727: The values of variables may be interrogated with the
728: .Ic display
729: command.
730: The variables which may be set or unset, but not toggled, are
731: listed here. In addition, any of the variables for the
732: .Ic toggle
733: command may be explicitly set or unset using
734: the
735: .Ic set
736: and
737: .Ic unset
738: commands.
739: .Bl -tag -width escape
740: .It Ic ayt
741: If
742: .Tn TELNET
743: is in localchars mode, or
744: .Dv LINEMODE
745: is enabled, and the status character is typed, a
746: .Dv TELNET AYT
747: sequence (see
748: .Ic send ayt
749: preceding) is sent to the
750: remote host. The initial value for the "Are You There"
751: character is the terminal's status character.
752: .It Ic echo
753: This is the value (initially \*(Lq^E\*(Rq) which, when in
754: \*(Lqline by line\*(Rq mode, toggles between doing local echoing
755: of entered characters (for normal processing), and suppressing
756: echoing of entered characters (for entering, say, a password).
757: .It Ic eof
758: If
759: .Nm telnet
760: is operating in
761: .Dv LINEMODE
762: or \*(Lqold line by line\*(Rq mode, entering this character
763: as the first character on a line will cause this character to be
764: sent to the remote system.
765: The initial value of the eof character is taken to be the terminal's
766: .Ic eof
767: character.
768: .It Ic erase
769: If
770: .Nm telnet
771: is in
772: .Ic localchars
773: mode (see
774: .Ic toggle
775: .Ic localchars
776: below),
777: .Sy and
778: if
779: .Nm telnet
780: is operating in \*(Lqcharacter at a time\*(Rq mode, then when this
781: character is typed, a
782: .Dv TELNET EC
783: sequence (see
784: .Ic send
785: .Ic ec
786: above)
787: is sent to the remote system.
788: The initial value for the erase character is taken to be
789: the terminal's
790: .Ic erase
791: character.
792: .It Ic escape
793: This is the
794: .Nm telnet
795: escape character (initially \*(Lq^[\*(Rq) which causes entry
796: into
797: .Nm telnet
798: command mode (when connected to a remote system).
799: .It Ic flushoutput
800: If
801: .Nm telnet
802: is in
803: .Ic localchars
804: mode (see
805: .Ic toggle
806: .Ic localchars
807: below)
808: and the
809: .Ic flushoutput
810: character is typed, a
811: .Dv TELNET AO
812: sequence (see
813: .Ic send
814: .Ic ao
815: above)
816: is sent to the remote host.
817: The initial value for the flush character is taken to be
818: the terminal's
819: .Ic flush
820: character.
821: .It Ic forw1
822: .It Ic forw2
823: If
824: .Tn TELNET
825: is operating in
826: .Dv LINEMODE ,
827: these are the
828: characters that, when typed, cause partial lines to be
829: forwarded to the remote system. The initial value for
830: the forwarding characters are taken from the terminal's
831: eol and eol2 characters.
832: .It Ic interrupt
833: If
834: .Nm telnet
835: is in
836: .Ic localchars
837: mode (see
838: .Ic toggle
839: .Ic localchars
840: below)
841: and the
842: .Ic interrupt
843: character is typed, a
844: .Dv TELNET IP
845: sequence (see
846: .Ic send
847: .Ic ip
848: above)
849: is sent to the remote host.
850: The initial value for the interrupt character is taken to be
851: the terminal's
852: .Ic intr
853: character.
854: .It Ic kill
855: If
856: .Nm telnet
857: is in
858: .Ic localchars
859: mode (see
860: .Ic toggle
861: .Ic localchars
862: below),
863: .Ic and
864: if
865: .Nm telnet
866: is operating in \*(Lqcharacter at a time\*(Rq mode, then when this
867: character is typed, a
868: .Dv TELNET EL
869: sequence (see
870: .Ic send
871: .Ic el
872: above)
873: is sent to the remote system.
874: The initial value for the kill character is taken to be
875: the terminal's
876: .Ic kill
877: character.
878: .It Ic lnext
879: If
880: .Nm telnet
881: is operating in
882: .Dv LINEMODE
883: or \*(Lqold line by line\*(Lq mode, then this character is taken to
884: be the terminal's
885: .Ic lnext
886: character.
887: The initial value for the lnext character is taken to be
888: the terminal's
889: .Ic lnext
890: character.
891: .It Ic quit
892: If
893: .Nm telnet
894: is in
895: .Ic localchars
896: mode (see
897: .Ic toggle
898: .Ic localchars
899: below)
900: and the
901: .Ic quit
902: character is typed, a
903: .Dv TELNET BRK
904: sequence (see
905: .Ic send
906: .Ic brk
907: above)
908: is sent to the remote host.
909: The initial value for the quit character is taken to be
910: the terminal's
911: .Ic quit
912: character.
913: .It Ic reprint
914: If
915: .Nm telnet
916: is operating in
917: .Dv LINEMODE
918: or \*(Lqold line by line\*(Lq mode, then this character is taken to
919: be the terminal's
920: .Ic reprint
921: character.
922: The initial value for the reprint character is taken to be
923: the terminal's
924: .Ic reprint
925: character.
926: .It Ic rlogin
927: This is the rlogin escape character.
928: If set, the normal
929: .Tn TELNET
930: escape character is ignored unless it is
931: preceded by this character at the beginning of a line.
932: This character, at the beginning of a line followed by
933: a "." closes the connection; when followed by a ^Z it
934: suspends the telnet command. The initial state is to
935: disable the rlogin escape character.
936: .It Ic start
937: If the
938: .Dv TELNET TOGGLE-FLOW-CONTROL
939: option has been enabled,
940: then this character is taken to
941: be the terminal's
942: .Ic start
943: character.
944: The initial value for the kill character is taken to be
945: the terminal's
946: .Ic start
947: character.
948: .It Ic stop
949: If the
950: .Dv TELNET TOGGLE-FLOW-CONTROL
951: option has been enabled,
952: then this character is taken to
953: be the terminal's
954: .Ic stop
955: character.
956: The initial value for the kill character is taken to be
957: the terminal's
958: .Ic stop
959: character.
960: .It Ic susp
961: If
962: .Nm telnet
963: is in
964: .Ic localchars
965: mode, or
966: .Dv LINEMODE
967: is enabled, and the
968: .Ic suspend
969: character is typed, a
970: .Dv TELNET SUSP
971: sequence (see
972: .Ic send
973: .Ic susp
974: above)
975: is sent to the remote host.
976: The initial value for the suspend character is taken to be
977: the terminal's
978: .Ic suspend
979: character.
980: .It Ic tracefile
981: This is the file to which the output, caused by
982: .Ic netdata
983: or
984: .Ic option
985: tracing being
986: .Dv TRUE ,
987: will be written. If it is set to
988: .Dq Fl ,
989: then tracing information will be written to standard output (the default).
990: .It Ic worderase
991: If
992: .Nm telnet
993: is operating in
994: .Dv LINEMODE
995: or \*(Lqold line by line\*(Lq mode, then this character is taken to
996: be the terminal's
997: .Ic worderase
998: character.
999: The initial value for the worderase character is taken to be
1000: the terminal's
1001: .Ic worderase
1002: character.
1003: .It Ic \&?
1004: Displays the legal
1005: .Ic set
1006: .Pq Ic unset
1007: commands.
1008: .El
1009: .It Ic slc Ar state
1010: The
1011: .Ic slc
1012: command (Set Local Characters) is used to set
1013: or change the state of the the special
1014: characters when the
1015: .Dv TELNET LINEMODE
1016: option has
1017: been enabled. Special characters are characters that get
1018: mapped to
1019: .Tn TELNET
1020: commands sequences (like
1021: .Ic ip
1022: or
1023: .Ic quit )
1024: or line editing characters (like
1025: .Ic erase
1026: and
1027: .Ic kill ) .
1028: By default, the local special characters are exported.
1029: .Bl -tag -width Fl
1030: .It Ic check
1031: Verify the current settings for the current special characters.
1032: The remote side is requested to send all the current special
1033: character settings, and if there are any discrepancies with
1034: the local side, the local side will switch to the remote value.
1035: .It Ic export
1036: Switch to the local defaults for the special characters. The
1037: local default characters are those of the local terminal at
1038: the time when
1039: .Nm telnet
1040: was started.
1041: .It Ic import
1042: Switch to the remote defaults for the special characters.
1043: The remote default characters are those of the remote system
1044: at the time when the
1045: .Tn TELNET
1046: connection was established.
1047: .It Ic \&?
1048: Prints out help information for the
1049: .Ic slc
1050: command.
1051: .El
1052: .It Ic status
1053: Show the current status of
1054: .Nm telnet .
1055: This includes the peer one is connected to, as well
1056: as the current mode.
1057: .It Ic toggle Ar arguments ...
1058: Toggle (between
1059: .Dv TRUE
1060: and
1061: .Dv FALSE )
1062: various flags that control how
1063: .Nm telnet
1064: responds to events.
1065: These flags may be set explicitly to
1066: .Dv TRUE
1067: or
1068: .Dv FALSE
1069: using the
1070: .Ic set
1071: and
1072: .Ic unset
1073: commands listed above.
1074: More than one argument may be specified.
1075: The state of these flags may be interrogated with the
1076: .Ic display
1077: command.
1078: Valid arguments are:
1079: .Bl -tag -width Ar
1080: .It Ic authdebug
1081: Turns on debugging information for the authentication code.
1082: .It Ic autoflush
1083: If
1084: .Ic autoflush
1085: and
1086: .Ic localchars
1087: are both
1088: .Dv TRUE ,
1089: then when the
1090: .Ic ao ,
1091: or
1092: .Ic quit
1093: characters are recognized (and transformed into
1094: .Tn TELNET
1095: sequences; see
1096: .Ic set
1097: above for details),
1098: .Nm telnet
1099: refuses to display any data on the user's terminal
1100: until the remote system acknowledges (via a
1101: .Dv TELNET TIMING MARK
1102: option)
1103: that it has processed those
1104: .Tn TELNET
1105: sequences.
1106: The initial value for this toggle is
1107: .Dv TRUE
1108: if the terminal user had not
1109: done an "stty noflsh", otherwise
1110: .Dv FALSE
1111: (see
1112: .Xr stty 1 ) .
1113: .It Ic autodecrypt
1114: When the
1115: .Dv TELNET ENCRYPT
1116: option is negotiated, by
1117: default the actual encryption (decryption) of the data
1118: stream does not start automatically. The autoencrypt
1119: (autodecrypt) command states that encryption of the
1120: output (input) stream should be enabled as soon as
1121: possible.
1122: .Pp
1123: Note: Because of export controls, the
1124: .Dv TELNET ENCRYPT
1125: option is not supported outside the United States and Canada.
1126: .It Ic autologin
1127: If the remote side supports the
1128: .Dv TELNET AUTHENTICATION
1129: option
1130: .Tn TELNET
1131: attempts to use it to perform automatic authentication. If the
1132: .Dv AUTHENTICATION
1133: option is not supported, the user's login
1134: name are propagated through the
1135: .Dv TELNET ENVIRON
1136: option.
1137: This command is the same as specifying
1138: .Ar a
1139: option on the
1140: .Ic open
1141: command.
1142: .It Ic autosynch
1143: If
1144: .Ic autosynch
1145: and
1146: .Ic localchars
1147: are both
1148: .Dv TRUE ,
1149: then when either the
1150: .Ic intr
1151: or
1152: .Ic quit
1153: characters is typed (see
1154: .Ic set
1155: above for descriptions of the
1156: .Ic intr
1157: and
1158: .Ic quit
1159: characters), the resulting
1160: .Tn TELNET
1161: sequence sent is followed by the
1162: .Dv TELNET SYNCH
1163: sequence.
1164: This procedure
1165: .Ic should
1166: cause the remote system to begin throwing away all previously
1167: typed input until both of the
1168: .Tn TELNET
1169: sequences have been read and acted upon.
1170: The initial value of this toggle is
1171: .Dv FALSE .
1172: .It Ic binary
1173: Enable or disable the
1174: .Dv TELNET BINARY
1175: option on both input and output.
1176: .It Ic inbinary
1177: Enable or disable the
1178: .Dv TELNET BINARY
1179: option on input.
1180: .It Ic outbinary
1181: Enable or disable the
1182: .Dv TELNET BINARY
1183: option on output.
1184: .It Ic crlf
1185: If this is
1186: .Dv TRUE ,
1187: then carriage returns will be sent as
1188: .Li <CR><LF> .
1189: If this is
1190: .Dv FALSE ,
1191: then carriage returns will be send as
1192: .Li <CR><NUL> .
1193: The initial value for this toggle is
1194: .Dv FALSE .
1195: .It Ic crmod
1196: Toggle carriage return mode.
1197: When this mode is enabled, most carriage return characters received from
1198: the remote host will be mapped into a carriage return followed by
1199: a line feed.
1200: This mode does not affect those characters typed by the user, only
1201: those received from the remote host.
1202: This mode is not very useful unless the remote host
1203: only sends carriage return, but never line feed.
1204: The initial value for this toggle is
1205: .Dv FALSE .
1206: .It Ic debug
1207: Toggles socket level debugging (useful only to the
1208: .Ic super user ) .
1209: The initial value for this toggle is
1210: .Dv FALSE .
1211: .It Ic encdebug
1212: Turns on debugging information for the encryption code.
1213: .It Ic localchars
1214: If this is
1215: .Dv TRUE ,
1216: then the
1217: .Ic flush ,
1218: .Ic interrupt ,
1219: .Ic quit ,
1220: .Ic erase ,
1221: and
1222: .Ic kill
1223: characters (see
1224: .Ic set
1225: above) are recognized locally, and transformed into (hopefully) appropriate
1226: .Tn TELNET
1227: control sequences
1228: (respectively
1229: .Ic ao ,
1230: .Ic ip ,
1231: .Ic brk ,
1232: .Ic ec ,
1233: and
1234: .Ic el ;
1235: see
1236: .Ic send
1237: above).
1238: The initial value for this toggle is
1239: .Dv TRUE
1240: in \*(Lqold line by line\*(Rq mode,
1241: and
1242: .Dv FALSE
1243: in \*(Lqcharacter at a time\*(Rq mode.
1244: When the
1245: .Dv LINEMODE
1246: option is enabled, the value of
1247: .Ic localchars
1248: is ignored, and assumed to always be
1249: .Dv TRUE .
1250: If
1251: .Dv LINEMODE
1252: has ever been enabled, then
1253: .Ic quit
1254: is sent as
1255: .Ic abort ,
1256: and
1257: .Ic eof and
1258: .B suspend
1259: are sent as
1260: .Ic eof and
1261: .Ic susp ,
1262: see
1263: .Ic send
1264: above).
1265: .It Ic netdata
1266: Toggles the display of all network data (in hexadecimal format).
1267: The initial value for this toggle is
1268: .Dv FALSE .
1269: .It Ic options
1270: Toggles the display of some internal
1271: .Nm telnet
1272: protocol processing (having to do with
1273: .Tn TELNET
1274: options).
1275: The initial value for this toggle is
1276: .Dv FALSE .
1277: .It Ic prettydump
1278: When the
1279: .Ic netdata
1280: toggle is enabled, if
1281: .Ic prettydump
1282: is enabled the output from the
1283: .Ic netdata
1284: command will be formatted in a more user readable format.
1285: Spaces are put between each character in the output, and the
1286: beginning of any
1287: .Tn TELNET
1288: escape sequence is preceded by a '*' to aid in locating them.
1289: .It Ic skiprc
1290: When the skiprc toggle is
1291: .Dv TRUE ,
1292: .Tn TELNET
1293: skips the reading of the
1294: .Pa \&.telnetrc
1295: file in the users home
1296: directory when connections are opened. The initial
1297: value for this toggle is
1298: .Dv FALSE.
1299: .It Ic termdata
1300: Toggles the display of all terminal data (in hexadecimal format).
1301: The initial value for this toggle is
1302: .Dv FALSE .
1303: .It Ic verbose_encrypt
1304: When the
1305: .Ic verbose_encrypt
1306: toggle is
1307: .Dv TRUE ,
1308: .Tn TELNET
1309: prints out a message each time encryption is enabled or
1310: disabled. The initial value for this toggle is
1311: .Dv FALSE.
1312: Note: Because of export controls, data encryption
1313: is not supported outside of the United States and Canada.
1314: .It Ic \&?
1315: Displays the legal
1316: .Ic toggle
1317: commands.
1318: .El
1319: .It Ic z
1320: Suspend
1321: .Nm telnet .
1322: This command only works when the user is using the
1323: .Xr csh 1 .
1324: .It Ic \&! Op Ar command
1325: Execute a single command in a subshell on the local
1326: system. If
1327: .Ic command
1328: is omitted, then an interactive
1329: subshell is invoked.
1330: .It Ic \&? Op Ar command
1331: Get help. With no arguments,
1332: .Nm telnet
1333: prints a help summary.
1334: If a command is specified,
1335: .Nm telnet
1336: will print the help information for just that command.
1337: .El
1338: .Sh ENVIRONMENT
1339: .Nm Telnet
1340: uses at least the
1341: .Ev HOME ,
1342: .Ev SHELL ,
1343: .Ev DISPLAY ,
1344: and
1345: .Ev TERM
1346: environment variables.
1347: Other environment variables may be propagated
1348: to the other side via the
1349: .Dv TELNET ENVIRON
1350: option.
1351: .Sh FILES
1352: .Bl -tag -width ~/.telnetrc -compact
1353: .It Pa ~/.telnetrc
1354: user customized telnet startup values
1355: .El
1356: .Sh HISTORY
1357: The
1358: .Nm Telnet
1359: command appeared in
1360: .Bx 4.2 .
1361: .Sh NOTES
1362: .Pp
1363: On some remote systems, echo has to be turned off manually when in
1364: \*(Lqold line by line\*(Rq mode.
1365: .Pp
1366: In \*(Lqold line by line\*(Rq mode or
1367: .Dv LINEMODE
1368: the terminal's
1369: .Ic eof
1370: character is only recognized (and sent to the remote system)
1371: when it is the first character on a line.
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