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1 | .\" Copyright (c) 1983 The Regents of the University of California. |
2 | .\" All rights reserved. | |
ea3f50ea | 3 | .\" |
15f0bc38 | 4 | .\" %sccs.include.redist.man% |
ea3f50ea | 5 | .\" |
8832c633 | 6 | .\" @(#)telnetd.8 6.9 (Berkeley) %G% |
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7 | .\" |
8 | .TH TELNETD 8 "" | |
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9 | .UC 5 |
10 | .SH NAME | |
511d63d0 | 11 | telnetd \- DARPA TELNET protocol server |
ea3f50ea | 12 | .SH SYNOPSIS |
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13 | .B /etc/telnetd |
14 | [\fB\-debug\fP [\fIport\fP]] | |
15 | [\fB\-l] | |
16 | [\fB\-D options\fP] | |
17 | [\fB\-D report\fP] | |
18 | [\fB\-D exercise\fP] | |
19 | [\fB\-D netdata\fP] | |
20 | [\fB\-D ptydata\fP] | |
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21 | .SH DESCRIPTION |
22 | .I Telnetd | |
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23 | is a server which supports the DARPA standard |
24 | .B TELNET | |
25 | virtual terminal protocol. | |
26 | .I Telnetd | |
27 | is invoked by the internet server (see | |
28 | .IR inetd (8)), | |
29 | normally for requests to connect to the | |
30 | .B TELNET | |
31 | port as indicated by the | |
32 | .I /etc/services | |
33 | file (see | |
34 | .IR services (5)). | |
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35 | If the \fB\-debug\fP may be used, to start up \fBtelnetd\fP |
36 | manually, instead of through | |
37 | .IR inetd (8). | |
38 | If started up this way, \fIport\fP may be specified to | |
39 | run \fItelnetd\fP on an alternate TCP port number. | |
40 | .PP | |
41 | The \fB\-D\fP option may be used for debugging purposes. | |
42 | This allows \fItelnet\fR to print out debugging information | |
43 | to the connection, allowing the user to see what telnetd | |
44 | is doing. | |
45 | There are several modifiers: | |
46 | \fBoptions\fR prints information about the negotiation | |
47 | of \fBTELNET\fR options, | |
48 | \fBreport\fR prints the \fBoptions\fR information, plus | |
49 | some additional information about what processing is going on, | |
50 | \fBnetdata\fP displays the data stream received by \fItelnetd\fP, | |
51 | \fBptydata\fP displays data written to the pty, and | |
52 | \fBexercise\fR has not been implemented yet. | |
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53 | .PP |
54 | .I Telnetd | |
55 | operates by allocating a pseudo-terminal device (see | |
56 | .IR pty (4)) | |
57 | for a client, then creating a login process which has | |
58 | the slave side of the pseudo-terminal as | |
59 | .BR stdin , | |
60 | .BR stdout , | |
61 | and | |
62 | .BR stderr . | |
63 | .I Telnetd | |
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64 | manipulates the master side of the pseudo-terminal, |
65 | implementing the | |
66 | .B TELNET | |
67 | protocol and passing characters | |
68 | between the remote client and the login process. | |
ea3f50ea | 69 | .PP |
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70 | When a |
71 | .B TELNET | |
72 | session is started up, | |
ea3f50ea | 73 | .I telnetd |
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74 | sends |
75 | .B TELNET | |
76 | options to the client side indicating | |
77 | a willingness to do | |
78 | .I remote echo | |
79 | of characters, to | |
80 | .I suppress go | |
81 | .IR ahead , | |
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82 | to do |
83 | .I remote flow | |
84 | .IR control , | |
60577684 | 85 | and to receive |
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86 | .I terminal type |
87 | .IR information , | |
88 | .I terminal speed | |
89 | .IR information , | |
90 | and | |
91 | .I window size information | |
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92 | from the remote client. |
93 | If the remote client is willing, the remote terminal type is | |
94 | propagated in the environment of the created login process. | |
95 | The pseudo-terminal allocated to the client is configured | |
96 | to operate in \*(lqcooked\*(rq mode, and with XTABS and CRMOD | |
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97 | enabled (see |
98 | .IR tty (4)). | |
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99 | .PP |
100 | .I Telnetd | |
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101 | is willing to |
102 | .IR do : | |
103 | .IR echo , | |
104 | .IR binary , | |
105 | .I suppress go | |
106 | .IR ahead , | |
107 | and | |
108 | .I timing | |
109 | .IR mark . | |
110 | .I Telnetd | |
111 | is willing to have the remote client | |
112 | .IR do : | |
4a8a7128 | 113 | .IR linemode , |
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114 | .IR binary , |
115 | .I terminal | |
116 | .IR type , | |
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117 | .I terminal |
118 | .IR speed , | |
119 | .I window | |
120 | .IR size , | |
121 | .I toggle flow | |
122 | .IR control , | |
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123 | .IR environment , |
124 | .I X display | |
125 | .IR location , | |
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126 | and |
127 | .I suppress go | |
128 | .IR ahead . | |
ea3f50ea | 129 | .SH "SEE ALSO" |
ec338fb6 | 130 | telnet(1) |
ea3f50ea | 131 | .SH BUGS |
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132 | Some |
133 | .B TELNET | |
134 | commands are only partially implemented. | |
135 | .PP | |
60577684 | 136 | Because of bugs in the original 4.2 BSD |
ec338fb6 | 137 | .IR telnet (1), |
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138 | .I telnetd |
139 | performs some dubious protocol exchanges to try to discover if the remote | |
140 | client is, in fact, a 4.2 BSD | |
ec338fb6 | 141 | .IR telnet (1). |
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142 | .PP |
143 | .I Binary mode | |
144 | has no common interpretation except between similar operating systems | |
145 | (Unix in this case). | |
146 | .PP | |
147 | The terminal type name received from the remote client is converted to | |
148 | lower case. | |
149 | .PP | |
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150 | .I Telnetd |
151 | never sends | |
152 | .B TELNET | |
153 | .I go ahead | |
154 | commands. |