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b7080c8e A |
1 | .\" Copyright (c) 1983, 1993 |
2 | .\" The Regents of the University of California. All rights reserved. | |
3 | .\" | |
4 | .\" Redistribution and use in source and binary forms, with or without | |
5 | .\" modification, are permitted provided that the following conditions | |
6 | .\" are met: | |
7 | .\" 1. Redistributions of source code must retain the above copyright | |
8 | .\" notice, this list of conditions and the following disclaimer. | |
9 | .\" 2. Redistributions in binary form must reproduce the above copyright | |
10 | .\" notice, this list of conditions and the following disclaimer in the | |
11 | .\" documentation and/or other materials provided with the distribution. | |
12 | .\" 3. All advertising materials mentioning features or use of this software | |
13 | .\" must display the following acknowledgement: | |
14 | .\" This product includes software developed by the University of | |
15 | .\" California, Berkeley and its contributors. | |
16 | .\" 4. Neither the name of the University nor the names of its contributors | |
17 | .\" may be used to endorse or promote products derived from this software | |
18 | .\" without specific prior written permission. | |
19 | .\" | |
20 | .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
21 | .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
22 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
23 | .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
24 | .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
25 | .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
26 | .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
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29 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
30 | .\" SUCH DAMAGE. | |
31 | .\" | |
8052502f A |
32 | .\" @(#)telnetd.8 8.3 (Berkeley) 3/1/94 |
33 | .\" $FreeBSD: src/libexec/telnetd/telnetd.8,v 1.23 2001/07/15 07:53:42 dd Exp $ | |
b7080c8e | 34 | .\" |
8052502f | 35 | .Dd March 1, 1994 |
b7080c8e | 36 | .Dt TELNETD 8 |
8052502f | 37 | .Os |
b7080c8e A |
38 | .Sh NAME |
39 | .Nm telnetd | |
40 | .Nd DARPA | |
41 | .Tn TELNET | |
42 | protocol server | |
43 | .Sh SYNOPSIS | |
44 | .Nm /usr/libexec/telnetd | |
8052502f | 45 | .Op Fl Uhlkns |
b7080c8e A |
46 | .Op Fl D Ar debugmode |
47 | .Op Fl I Ns Ar initid | |
48 | .Op Fl S Ar tos | |
49 | .Op Fl X Ar authtype | |
50 | .Op Fl a Ar authmode | |
51 | .Op Fl edebug | |
8052502f | 52 | .Op Fl p Ar loginprog |
b7080c8e A |
53 | .Op Fl r Ns Ar lowpty-highpty |
54 | .Op Fl u Ar len | |
55 | .Op Fl debug Op Ar port | |
56 | .Sh DESCRIPTION | |
57 | The | |
8052502f | 58 | .Nm |
b7080c8e A |
59 | command is a server which supports the |
60 | .Tn DARPA | |
61 | standard | |
62 | .Tn TELNET | |
63 | virtual terminal protocol. | |
64 | .Nm Telnetd | |
65 | is normally invoked by the internet server (see | |
66 | .Xr inetd 8 ) | |
67 | for requests to connect to the | |
68 | .Tn TELNET | |
69 | port as indicated by the | |
70 | .Pa /etc/services | |
71 | file (see | |
72 | .Xr services 5 ) . | |
73 | The | |
74 | .Fl debug | |
75 | option may be used to start up | |
8052502f | 76 | .Nm |
b7080c8e A |
77 | manually, instead of through |
78 | .Xr inetd 8 . | |
8052502f | 79 | If started up this way, |
b7080c8e A |
80 | .Ar port |
81 | may be specified to run | |
8052502f | 82 | .Nm |
b7080c8e A |
83 | on an alternate |
84 | .Tn TCP | |
85 | port number. | |
86 | .Pp | |
87 | The | |
8052502f | 88 | .Nm |
b7080c8e | 89 | command accepts the following options: |
8052502f | 90 | .Bl -tag -width indent |
b7080c8e A |
91 | .It Fl a Ar authmode |
92 | This option may be used for specifying what mode should | |
93 | be used for authentication. | |
94 | Note that this option is only useful if | |
8052502f | 95 | .Nm |
b7080c8e A |
96 | has been compiled with support for the |
97 | .Dv AUTHENTICATION | |
98 | option. | |
99 | There are several valid values for | |
8052502f | 100 | .Ar authmode : |
b7080c8e | 101 | .Bl -tag -width debug |
8052502f A |
102 | .It Cm debug |
103 | Turn on authentication debugging code. | |
104 | .It Cm user | |
b7080c8e A |
105 | Only allow connections when the remote user |
106 | can provide valid authentication information | |
107 | to identify the remote user, | |
108 | and is allowed access to the specified account | |
109 | without providing a password. | |
8052502f | 110 | .It Cm valid |
b7080c8e A |
111 | Only allow connections when the remote user |
112 | can provide valid authentication information | |
113 | to identify the remote user. | |
114 | The | |
115 | .Xr login 1 | |
116 | command will provide any additional user verification | |
117 | needed if the remote user is not allowed automatic | |
118 | access to the specified account. | |
8052502f | 119 | .It Cm other |
b7080c8e A |
120 | Only allow connections that supply some authentication information. |
121 | This option is currently not supported | |
122 | by any of the existing authentication mechanisms, | |
123 | and is thus the same as specifying | |
124 | .Fl a | |
125 | .Cm valid . | |
8052502f | 126 | .It Cm none |
b7080c8e A |
127 | This is the default state. |
128 | Authentication information is not required. | |
129 | If no or insufficient authentication information | |
130 | is provided, then the | |
131 | .Xr login 1 | |
132 | program will provide the necessary user | |
133 | verification. | |
8052502f A |
134 | .It Cm off |
135 | Disable the authentication code. | |
b7080c8e A |
136 | All user verification will happen through the |
137 | .Xr login 1 | |
138 | program. | |
139 | .El | |
b7080c8e A |
140 | .It Fl D Ar debugmode |
141 | This option may be used for debugging purposes. | |
142 | This allows | |
8052502f | 143 | .Nm |
b7080c8e A |
144 | to print out debugging information |
145 | to the connection, allowing the user to see what | |
8052502f | 146 | .Nm |
b7080c8e | 147 | is doing. |
8052502f A |
148 | There are several possible values for |
149 | .Ar debugmode : | |
b7080c8e A |
150 | .Bl -tag -width exercise |
151 | .It Cm options | |
8052502f | 152 | Print information about the negotiation of |
b7080c8e A |
153 | .Tn TELNET |
154 | options. | |
155 | .It Cm report | |
8052502f | 156 | Print the |
b7080c8e A |
157 | .Cm options |
158 | information, plus some additional information | |
159 | about what processing is going on. | |
160 | .It Cm netdata | |
8052502f A |
161 | Display the data stream received by |
162 | .Nm . | |
b7080c8e | 163 | .It Cm ptydata |
8052502f | 164 | Display data written to the pty. |
b7080c8e A |
165 | .It Cm exercise |
166 | Has not been implemented yet. | |
167 | .El | |
168 | .It Fl debug | |
8052502f A |
169 | Enable debugging on each socket created by |
170 | .Nm | |
b7080c8e A |
171 | (see |
172 | .Dv SO_DEBUG | |
173 | in | |
174 | .Xr socket 2 ) . | |
175 | .It Fl edebug | |
176 | If | |
8052502f | 177 | .Nm |
b7080c8e A |
178 | has been compiled with support for data encryption, then the |
179 | .Fl edebug | |
180 | option may be used to enable encryption debugging code. | |
8052502f A |
181 | .It Fl p Ar loginprog |
182 | Specify an alternate | |
183 | .Xr login 1 | |
184 | command to run to complete the login. The alternate command must | |
185 | understand the same command arguments as the standard login. | |
b7080c8e | 186 | .It Fl h |
8052502f | 187 | Disable the printing of host-specific information before |
b7080c8e A |
188 | login has been completed. |
189 | .It Fl I Ar initid | |
190 | This option is only applicable to | |
191 | .Tn UNICOS | |
192 | systems prior to 7.0. | |
193 | It specifies the | |
194 | .Dv ID | |
195 | from | |
196 | .Pa /etc/inittab | |
197 | to use when init starts login sessions. The default | |
198 | .Dv ID | |
199 | is | |
8052502f | 200 | .Dv fe . |
b7080c8e A |
201 | .It Fl k |
202 | This option is only useful if | |
8052502f | 203 | .Nm |
b7080c8e A |
204 | has been compiled with both linemode and kludge linemode |
205 | support. If the | |
206 | .Fl k | |
207 | option is specified, then if the remote client does not | |
208 | support the | |
209 | .Dv LINEMODE | |
210 | option, then | |
8052502f | 211 | .Nm |
b7080c8e A |
212 | will operate in character at a time mode. |
213 | It will still support kludge linemode, but will only | |
214 | go into kludge linemode if the remote client requests | |
215 | it. | |
8052502f | 216 | (This is done by the client sending |
b7080c8e A |
217 | .Dv DONT SUPPRESS-GO-AHEAD |
218 | and | |
219 | .Dv DONT ECHO . ) | |
220 | The | |
221 | .Fl k | |
222 | option is most useful when there are remote clients | |
223 | that do not support kludge linemode, but pass the heuristic | |
224 | (if they respond with | |
225 | .Dv WILL TIMING-MARK | |
226 | in response to a | |
8052502f | 227 | .Dv DO TIMING-MARK ) |
b7080c8e A |
228 | for kludge linemode support. |
229 | .It Fl l | |
8052502f | 230 | Specify line mode. Try to force clients to use line- |
b7080c8e A |
231 | at-a-time mode. |
232 | If the | |
233 | .Dv LINEMODE | |
234 | option is not supported, it will go | |
235 | into kludge linemode. | |
236 | .It Fl n | |
237 | Disable | |
238 | .Dv TCP | |
239 | keep-alives. Normally | |
8052502f | 240 | .Nm |
b7080c8e A |
241 | enables the |
242 | .Tn TCP | |
243 | keep-alive mechanism to probe connections that | |
244 | have been idle for some period of time to determine | |
245 | if the client is still there, so that idle connections | |
246 | from machines that have crashed or can no longer | |
247 | be reached may be cleaned up. | |
248 | .It Fl r Ar lowpty-highpty | |
249 | This option is only enabled when | |
8052502f | 250 | .Nm |
b7080c8e | 251 | is compiled for |
8052502f | 252 | .Dv UNICOS . |
b7080c8e A |
253 | It specifies an inclusive range of pseudo-terminal devices to |
254 | use. If the system has sysconf variable | |
255 | .Dv _SC_CRAY_NPTY | |
256 | configured, the default pty search range is 0 to | |
8052502f | 257 | .Dv _SC_CRAY_NPTY ; |
b7080c8e A |
258 | otherwise, the default range is 0 to 128. Either |
259 | .Ar lowpty | |
260 | or | |
261 | .Ar highpty | |
262 | may be omitted to allow changing | |
263 | either end of the search range. If | |
264 | .Ar lowpty | |
265 | is omitted, the - character is still required so that | |
8052502f | 266 | .Nm |
b7080c8e A |
267 | can differentiate |
268 | .Ar highpty | |
269 | from | |
270 | .Ar lowpty . | |
271 | .It Fl s | |
272 | This option is only enabled if | |
8052502f | 273 | .Nm |
b7080c8e A |
274 | is compiled with support for |
275 | .Tn SecurID | |
276 | cards. | |
277 | It causes the | |
278 | .Fl s | |
279 | option to be passed on to | |
280 | .Xr login 1 , | |
281 | and thus is only useful if | |
282 | .Xr login 1 | |
283 | supports the | |
284 | .Fl s | |
285 | flag to indicate that only | |
286 | .Tn SecurID | |
287 | validated logins are allowed, and is | |
288 | usually useful for controlling remote logins | |
289 | from outside of a firewall. | |
290 | .It Fl S Ar tos | |
291 | .It Fl u Ar len | |
292 | This option is used to specify the size of the field | |
293 | in the | |
294 | .Dv utmp | |
295 | structure that holds the remote host name. | |
296 | If the resolved host name is longer than | |
297 | .Ar len , | |
298 | the dotted decimal value will be used instead. | |
299 | This allows hosts with very long host names that | |
300 | overflow this field to still be uniquely identified. | |
301 | Specifying | |
302 | .Fl u0 | |
303 | indicates that only dotted decimal addresses | |
304 | should be put into the | |
305 | .Pa utmp | |
306 | file. | |
b7080c8e A |
307 | .It Fl U |
308 | This option causes | |
8052502f | 309 | .Nm |
b7080c8e A |
310 | to refuse connections from addresses that |
311 | cannot be mapped back into a symbolic name | |
312 | via the | |
313 | .Xr gethostbyaddr 3 | |
314 | routine. | |
315 | .It Fl X Ar authtype | |
316 | This option is only valid if | |
8052502f | 317 | .Nm |
b7080c8e A |
318 | has been built with support for the authentication option. |
319 | It disables the use of | |
320 | .Ar authtype | |
321 | authentication, and | |
322 | can be used to temporarily disable | |
323 | a specific authentication type without having to recompile | |
8052502f | 324 | .Nm . |
b7080c8e A |
325 | .El |
326 | .Pp | |
327 | .Nm Telnetd | |
328 | operates by allocating a pseudo-terminal device (see | |
329 | .Xr pty 4 ) | |
330 | for a client, then creating a login process which has | |
8052502f | 331 | the slave side of the pseudo-terminal as |
b7080c8e A |
332 | .Dv stdin , |
333 | .Dv stdout | |
334 | and | |
335 | .Dv stderr . | |
336 | .Nm Telnetd | |
337 | manipulates the master side of the pseudo-terminal, | |
338 | implementing the | |
339 | .Tn TELNET | |
340 | protocol and passing characters | |
341 | between the remote client and the login process. | |
342 | .Pp | |
343 | When a | |
344 | .Tn TELNET | |
8052502f A |
345 | session is started up, |
346 | .Nm | |
b7080c8e A |
347 | sends |
348 | .Tn TELNET | |
349 | options to the client side indicating | |
350 | a willingness to do the | |
351 | following | |
352 | .Tn TELNET | |
353 | options, which are described in more detail below: | |
354 | .Bd -literal -offset indent | |
355 | DO AUTHENTICATION | |
356 | WILL ENCRYPT | |
357 | DO TERMINAL TYPE | |
358 | DO TSPEED | |
359 | DO XDISPLOC | |
360 | DO NEW-ENVIRON | |
361 | DO ENVIRON | |
362 | WILL SUPPRESS GO AHEAD | |
363 | DO ECHO | |
364 | DO LINEMODE | |
365 | DO NAWS | |
366 | WILL STATUS | |
367 | DO LFLOW | |
368 | DO TIMING-MARK | |
369 | .Ed | |
370 | .Pp | |
371 | The pseudo-terminal allocated to the client is configured | |
8052502f A |
372 | to operate in |
373 | .Dq cooked | |
374 | mode, and with | |
b7080c8e A |
375 | .Dv XTABS and |
376 | .Dv CRMOD | |
377 | enabled (see | |
378 | .Xr tty 4 ) . | |
379 | .Pp | |
380 | .Nm Telnetd | |
381 | has support for enabling locally the following | |
382 | .Tn TELNET | |
383 | options: | |
384 | .Bl -tag -width "DO AUTHENTICATION" | |
385 | .It "WILL ECHO" | |
386 | When the | |
387 | .Dv LINEMODE | |
388 | option is enabled, a | |
389 | .Dv WILL ECHO | |
390 | or | |
391 | .Dv WONT ECHO | |
392 | will be sent to the client to indicate the | |
393 | current state of terminal echoing. | |
394 | When terminal echo is not desired, a | |
395 | .Dv WILL ECHO | |
396 | is sent to indicate that | |
8052502f | 397 | .Nm |
b7080c8e A |
398 | will take care of echoing any data that needs to be |
399 | echoed to the terminal, and then nothing is echoed. | |
400 | When terminal echo is desired, a | |
401 | .Dv WONT ECHO | |
402 | is sent to indicate that | |
8052502f | 403 | .Nm |
b7080c8e A |
404 | will not be doing any terminal echoing, so the |
405 | client should do any terminal echoing that is needed. | |
406 | .It "WILL BINARY" | |
8052502f | 407 | Indicate that the client is willing to send a |
b7080c8e A |
408 | 8 bits of data, rather than the normal 7 bits |
409 | of the Network Virtual Terminal. | |
410 | .It "WILL SGA" | |
8052502f A |
411 | Indicate that it will not be sending |
412 | .Dv IAC GA , | |
b7080c8e A |
413 | go ahead, commands. |
414 | .It "WILL STATUS" | |
8052502f | 415 | Indicate a willingness to send the client, upon |
b7080c8e A |
416 | request, of the current status of all |
417 | .Tn TELNET | |
418 | options. | |
419 | .It "WILL TIMING-MARK" | |
420 | Whenever a | |
421 | .Dv DO TIMING-MARK | |
422 | command is received, it is always responded | |
423 | to with a | |
8052502f | 424 | .Dv WILL TIMING-MARK . |
b7080c8e A |
425 | .It "WILL LOGOUT" |
426 | When a | |
427 | .Dv DO LOGOUT | |
428 | is received, a | |
429 | .Dv WILL LOGOUT | |
430 | is sent in response, and the | |
431 | .Tn TELNET | |
432 | session is shut down. | |
433 | .It "WILL ENCRYPT" | |
434 | Only sent if | |
8052502f | 435 | .Nm |
b7080c8e A |
436 | is compiled with support for data encryption, and |
437 | indicates a willingness to decrypt | |
438 | the data stream. | |
439 | .El | |
440 | .Pp | |
441 | .Nm Telnetd | |
442 | has support for enabling remotely the following | |
443 | .Tn TELNET | |
444 | options: | |
445 | .Bl -tag -width "DO AUTHENTICATION" | |
446 | .It "DO BINARY" | |
447 | Sent to indicate that | |
8052502f | 448 | .Nm |
b7080c8e A |
449 | is willing to receive an 8 bit data stream. |
450 | .It "DO LFLOW" | |
451 | Requests that the client handle flow control | |
452 | characters remotely. | |
453 | .It "DO ECHO" | |
454 | This is not really supported, but is sent to identify a 4.2BSD | |
455 | .Xr telnet 1 | |
456 | client, which will improperly respond with | |
8052502f | 457 | .Dv WILL ECHO . |
b7080c8e A |
458 | If a |
459 | .Dv WILL ECHO | |
460 | is received, a | |
461 | .Dv DONT ECHO | |
462 | will be sent in response. | |
463 | .It "DO TERMINAL-TYPE" | |
8052502f | 464 | Indicate a desire to be able to request the |
b7080c8e A |
465 | name of the type of terminal that is attached |
466 | to the client side of the connection. | |
467 | .It "DO SGA" | |
8052502f A |
468 | Indicate that it does not need to receive |
469 | .Dv IAC GA , | |
b7080c8e A |
470 | the go ahead command. |
471 | .It "DO NAWS" | |
472 | Requests that the client inform the server when | |
473 | the window (display) size changes. | |
474 | .It "DO TERMINAL-SPEED" | |
8052502f | 475 | Indicate a desire to be able to request information |
b7080c8e A |
476 | about the speed of the serial line to which |
477 | the client is attached. | |
478 | .It "DO XDISPLOC" | |
8052502f A |
479 | Indicate a desire to be able to request the name |
480 | of the X Window System display that is associated with | |
b7080c8e A |
481 | the telnet client. |
482 | .It "DO NEW-ENVIRON" | |
8052502f | 483 | Indicate a desire to be able to request environment |
b7080c8e A |
484 | variable information, as described in RFC 1572. |
485 | .It "DO ENVIRON" | |
8052502f | 486 | Indicate a desire to be able to request environment |
b7080c8e A |
487 | variable information, as described in RFC 1408. |
488 | .It "DO LINEMODE" | |
489 | Only sent if | |
8052502f | 490 | .Nm |
b7080c8e A |
491 | is compiled with support for linemode, and |
492 | requests that the client do line by line processing. | |
493 | .It "DO TIMING-MARK" | |
494 | Only sent if | |
8052502f | 495 | .Nm |
b7080c8e A |
496 | is compiled with support for both linemode and |
497 | kludge linemode, and the client responded with | |
8052502f | 498 | .Dv WONT LINEMODE . |
b7080c8e | 499 | If the client responds with |
8052502f | 500 | .Dv WILL TM , |
b7080c8e A |
501 | the it is assumed that the client supports |
502 | kludge linemode. | |
503 | Note that the | |
504 | .Op Fl k | |
505 | option can be used to disable this. | |
506 | .It "DO AUTHENTICATION" | |
507 | Only sent if | |
8052502f | 508 | .Nm |
b7080c8e A |
509 | is compiled with support for authentication, and |
510 | indicates a willingness to receive authentication | |
511 | information for automatic login. | |
512 | .It "DO ENCRYPT" | |
513 | Only sent if | |
8052502f | 514 | .Nm |
b7080c8e A |
515 | is compiled with support for data encryption, and |
516 | indicates a willingness to decrypt | |
517 | the data stream. | |
8052502f A |
518 | .El |
519 | .Sh NOTES | |
520 | By default | |
521 | .Nm | |
522 | will read the | |
523 | .Em \&he , | |
524 | .Em \&hn , | |
525 | and | |
526 | .Em \&im | |
527 | capabilities from | |
528 | .Pa /etc/gettytab | |
529 | and use that information (if present) to determine | |
530 | what to display before the login: prompt. You can | |
531 | also use a System V style | |
532 | .Pa /etc/issue | |
533 | file by using the | |
534 | .Em \&if | |
535 | capability, which will override | |
536 | .Em \&im . | |
537 | The information specified in either | |
538 | .Em \&im | |
539 | or | |
540 | .Em \&if | |
541 | will be displayed to both console and remote logins. | |
542 | .\" .Sh ENVIRONMENT | |
b7080c8e | 543 | .Sh FILES |
8052502f A |
544 | .Bl -tag -width /usr/ucb/bftp -compact |
545 | .It Pa /etc/services | |
546 | .It Pa /etc/gettytab | |
547 | .It Pa /etc/inittab | |
b7080c8e | 548 | (UNICOS systems only) |
8052502f | 549 | .It Pa /etc/iptos |
b7080c8e | 550 | (if supported) |
8052502f | 551 | .It Pa /usr/ucb/bftp |
b7080c8e | 552 | (if supported) |
8052502f | 553 | .El |
b7080c8e | 554 | .Sh "SEE ALSO" |
8052502f | 555 | .Xr bftp 1 , |
b7080c8e | 556 | .Xr login 1 , |
8052502f A |
557 | .Xr gettytab 5 , |
558 | .Xr telnet 1 | |
b7080c8e A |
559 | (if supported) |
560 | .Sh STANDARDS | |
561 | .Bl -tag -compact -width RFC-1572 | |
562 | .It Cm RFC-854 | |
563 | .Tn TELNET | |
564 | PROTOCOL SPECIFICATION | |
565 | .It Cm RFC-855 | |
566 | TELNET OPTION SPECIFICATIONS | |
567 | .It Cm RFC-856 | |
568 | TELNET BINARY TRANSMISSION | |
569 | .It Cm RFC-857 | |
570 | TELNET ECHO OPTION | |
571 | .It Cm RFC-858 | |
572 | TELNET SUPPRESS GO AHEAD OPTION | |
573 | .It Cm RFC-859 | |
574 | TELNET STATUS OPTION | |
575 | .It Cm RFC-860 | |
576 | TELNET TIMING MARK OPTION | |
577 | .It Cm RFC-861 | |
578 | TELNET EXTENDED OPTIONS - LIST OPTION | |
579 | .It Cm RFC-885 | |
580 | TELNET END OF RECORD OPTION | |
581 | .It Cm RFC-1073 | |
582 | Telnet Window Size Option | |
583 | .It Cm RFC-1079 | |
584 | Telnet Terminal Speed Option | |
585 | .It Cm RFC-1091 | |
586 | Telnet Terminal-Type Option | |
587 | .It Cm RFC-1096 | |
588 | Telnet X Display Location Option | |
589 | .It Cm RFC-1123 | |
590 | Requirements for Internet Hosts -- Application and Support | |
591 | .It Cm RFC-1184 | |
592 | Telnet Linemode Option | |
593 | .It Cm RFC-1372 | |
594 | Telnet Remote Flow Control Option | |
595 | .It Cm RFC-1416 | |
596 | Telnet Authentication Option | |
597 | .It Cm RFC-1411 | |
598 | Telnet Authentication: Kerberos Version 4 | |
599 | .It Cm RFC-1412 | |
600 | Telnet Authentication: SPX | |
601 | .It Cm RFC-1571 | |
602 | Telnet Environment Option Interoperability Issues | |
603 | .It Cm RFC-1572 | |
604 | Telnet Environment Option | |
8052502f | 605 | .El |
b7080c8e A |
606 | .Sh BUGS |
607 | Some | |
608 | .Tn TELNET | |
609 | commands are only partially implemented. | |
610 | .Pp | |
611 | Because of bugs in the original 4.2 BSD | |
612 | .Xr telnet 1 , | |
8052502f | 613 | .Nm |
b7080c8e A |
614 | performs some dubious protocol exchanges to try to discover if the remote |
615 | client is, in fact, a 4.2 BSD | |
616 | .Xr telnet 1 . | |
617 | .Pp | |
618 | Binary mode | |
619 | has no common interpretation except between similar operating systems | |
620 | (Unix in this case). | |
621 | .Pp | |
622 | The terminal type name received from the remote client is converted to | |
623 | lower case. | |
624 | .Pp | |
625 | .Nm Telnetd | |
626 | never sends | |
627 | .Tn TELNET | |
628 | .Dv IAC GA | |
629 | (go ahead) commands. | |
8052502f A |
630 | .Sh HISTORY |
631 | IPv6 support was added by WIDE/KAME project. |