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1 | .\" Copyright (c) 1983 The Regents of the University of California. |
2 | .\" 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) | |
27 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
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29 | .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
30 | .\" SUCH DAMAGE. | |
31 | .\" | |
32 | .\" @(#)telnetd.8 6.8 (Berkeley) 4/20/91 | |
33 | .\" | |
34 | .TH TELNETD 8 "April 20, 1991" | |
35 | .UC 5 | |
36 | .SH NAME | |
37 | telnetd \- DARPA TELNET protocol server | |
38 | .SH SYNOPSIS | |
39 | .B /etc/telnetd | |
40 | [\fB\-debug\fP [\fIport\fP]] | |
41 | [\fB\-l] | |
42 | [\fB\-D options\fP] | |
43 | [\fB\-D report\fP] | |
44 | [\fB\-D exercise\fP] | |
45 | [\fB\-D netdata\fP] | |
46 | [\fB\-D ptydata\fP] | |
47 | .SH DESCRIPTION | |
48 | .I Telnetd | |
49 | is a server which supports the DARPA standard | |
50 | .B TELNET | |
51 | virtual terminal protocol. | |
52 | .I Telnetd | |
53 | is invoked by the internet server (see | |
54 | .IR inetd (8)), | |
55 | normally for requests to connect to the | |
56 | .B TELNET | |
57 | port as indicated by the | |
58 | .I /etc/services | |
59 | file (see | |
60 | .IR services (5)). | |
61 | If the \fB\-debug\fP may be used, to start up \fBtelnetd\fP | |
62 | manually, instead of through | |
63 | .IR inetd (8). | |
64 | If started up this way, \fIport\fP may be specified to | |
65 | run \fItelnetd\fP on an alternate TCP port number. | |
66 | .PP | |
67 | The \fB\-D\fP option may be used for debugging purposes. | |
68 | This allows \fItelnet\fR to print out debugging information | |
69 | to the connection, allowing the user to see what telnetd | |
70 | is doing. | |
71 | There are several modifiers: | |
72 | \fBoptions\fR prints information about the negotiation | |
73 | of \fBTELNET\fR options, | |
74 | \fBreport\fR prints the \fBoptions\fR information, plus | |
75 | some additional information about what processing is going on, | |
76 | \fBnetdata\fP displays the data stream received by \fItelnetd\fP, | |
77 | \fBptydata\fP displays data written to the pty, and | |
78 | \fBexercise\fR has not been implemented yet. | |
79 | .PP | |
80 | .I Telnetd | |
81 | operates by allocating a pseudo-terminal device (see | |
82 | .IR pty (4)) | |
83 | for a client, then creating a login process which has | |
84 | the slave side of the pseudo-terminal as | |
85 | .BR stdin , | |
86 | .BR stdout , | |
87 | and | |
88 | .BR stderr . | |
89 | .I Telnetd | |
90 | manipulates the master side of the pseudo-terminal, | |
91 | implementing the | |
92 | .B TELNET | |
93 | protocol and passing characters | |
94 | between the remote client and the login process. | |
95 | .PP | |
96 | When a | |
97 | .B TELNET | |
98 | session is started up, | |
99 | .I telnetd | |
100 | sends | |
101 | .B TELNET | |
102 | options to the client side indicating | |
103 | a willingness to do | |
104 | .I remote echo | |
105 | of characters, to | |
106 | .I suppress go | |
107 | .IR ahead , | |
108 | to do | |
109 | .I remote flow | |
110 | .IR control , | |
111 | and to receive | |
112 | .I terminal type | |
113 | .IR information , | |
114 | .I terminal speed | |
115 | .IR information , | |
116 | and | |
117 | .I window size information | |
118 | from the remote client. | |
119 | If the remote client is willing, the remote terminal type is | |
120 | propagated in the environment of the created login process. | |
121 | The pseudo-terminal allocated to the client is configured | |
122 | to operate in \*(lqcooked\*(rq mode, and with XTABS and CRMOD | |
123 | enabled (see | |
124 | .IR tty (4)). | |
125 | .PP | |
126 | .I Telnetd | |
127 | is willing to | |
128 | .IR do : | |
129 | .IR echo , | |
130 | .IR binary , | |
131 | .I suppress go | |
132 | .IR ahead , | |
133 | and | |
134 | .I timing | |
135 | .IR mark . | |
136 | .I Telnetd | |
137 | is willing to have the remote client | |
138 | .IR do : | |
139 | .IR linemode , | |
140 | .IR binary , | |
141 | .I terminal | |
142 | .IR type , | |
143 | .I terminal | |
144 | .IR speed , | |
145 | .I window | |
146 | .IR size , | |
147 | .I toggle flow | |
148 | .IR control , | |
149 | .IR environment , | |
150 | .I X display | |
151 | .IR location , | |
152 | and | |
153 | .I suppress go | |
154 | .IR ahead . | |
155 | .SH "SEE ALSO" | |
156 | telnet(1) | |
157 | .SH BUGS | |
158 | Some | |
159 | .B TELNET | |
160 | commands are only partially implemented. | |
161 | .PP | |
162 | Because of bugs in the original 4.2 BSD | |
163 | .IR telnet (1), | |
164 | .I telnetd | |
165 | performs some dubious protocol exchanges to try to discover if the remote | |
166 | client is, in fact, a 4.2 BSD | |
167 | .IR telnet (1). | |
168 | .PP | |
169 | .I Binary mode | |
170 | has no common interpretation except between similar operating systems | |
171 | (Unix in this case). | |
172 | .PP | |
173 | The terminal type name received from the remote client is converted to | |
174 | lower case. | |
175 | .PP | |
176 | .I Telnetd | |
177 | never sends | |
178 | .B TELNET | |
179 | .I go ahead | |
180 | commands. |