Commit | Line | Data |
---|---|---|
ea3f50ea KM |
1 | .\" Copyright (c) 1983 Regents of the University of California. |
2 | .\" All rights reserved. The Berkeley software License Agreement | |
3 | .\" specifies the terms and conditions for redistribution. | |
4 | .\" | |
511d63d0 | 5 | .\" @(#)telnetd.8 6.3 (Berkeley) %G% |
ea3f50ea | 6 | .\" |
b78cbcc5 | 7 | .TH TELNETD 8C "" |
ea3f50ea KM |
8 | .UC 5 |
9 | .SH NAME | |
511d63d0 | 10 | telnetd \- DARPA TELNET protocol server |
ea3f50ea KM |
11 | .SH SYNOPSIS |
12 | .B /etc/telnetd | |
ea3f50ea KM |
13 | .SH DESCRIPTION |
14 | .I Telnetd | |
60577684 GM |
15 | is a server which supports the DARPA standard |
16 | .B TELNET | |
17 | virtual terminal protocol. | |
18 | .I Telnetd | |
19 | is invoked by the internet server (see | |
20 | .IR inetd (8)), | |
21 | normally for requests to connect to the | |
22 | .B TELNET | |
23 | port as indicated by the | |
24 | .I /etc/services | |
25 | file (see | |
26 | .IR services (5)). | |
ea3f50ea KM |
27 | .PP |
28 | .I Telnetd | |
29 | operates by allocating a pseudo-terminal device (see | |
30 | .IR pty (4)) | |
31 | for a client, then creating a login process which has | |
32 | the slave side of the pseudo-terminal as | |
33 | .BR stdin , | |
34 | .BR stdout , | |
35 | and | |
36 | .BR stderr . | |
37 | .I Telnetd | |
60577684 GM |
38 | manipulates the master side of the pseudo-terminal, |
39 | implementing the | |
40 | .B TELNET | |
41 | protocol and passing characters | |
42 | between the remote client and the login process. | |
ea3f50ea | 43 | .PP |
60577684 GM |
44 | When a |
45 | .B TELNET | |
46 | session is started up, | |
ea3f50ea | 47 | .I telnetd |
60577684 GM |
48 | sends |
49 | .B TELNET | |
50 | options to the client side indicating | |
51 | a willingness to do | |
52 | .I remote echo | |
53 | of characters, to | |
54 | .I suppress go | |
55 | .IR ahead , | |
56 | and to receive | |
57 | .I terminal type information | |
58 | from the remote client. | |
59 | If the remote client is willing, the remote terminal type is | |
60 | propagated in the environment of the created login process. | |
61 | The pseudo-terminal allocated to the client is configured | |
62 | to operate in \*(lqcooked\*(rq mode, and with XTABS and CRMOD | |
ea3f50ea KM |
63 | enabled (see |
64 | .IR tty (4)). | |
ea3f50ea KM |
65 | .PP |
66 | .I Telnetd | |
60577684 GM |
67 | is willing to |
68 | .IR do : | |
69 | .IR echo , | |
70 | .IR binary , | |
71 | .I suppress go | |
72 | .IR ahead , | |
73 | and | |
74 | .I timing | |
75 | .IR mark . | |
76 | .I Telnetd | |
77 | is willing to have the remote client | |
78 | .IR do : | |
79 | .IR binary , | |
80 | .I terminal | |
81 | .IR type , | |
82 | and | |
83 | .I suppress go | |
84 | .IR ahead . | |
ea3f50ea KM |
85 | .SH "SEE ALSO" |
86 | telnet(1C) | |
87 | .SH BUGS | |
60577684 GM |
88 | Some |
89 | .B TELNET | |
90 | commands are only partially implemented. | |
91 | .PP | |
92 | The | |
93 | .B TELNET | |
94 | protocol allows for | |
95 | the exchange of the number of lines and columns on the user's terminal, | |
96 | but | |
97 | .I telnetd | |
98 | doesn't make use of them. | |
99 | .PP | |
100 | Because of bugs in the original 4.2 BSD | |
101 | .IR telnet (1C), | |
102 | .I telnetd | |
103 | performs some dubious protocol exchanges to try to discover if the remote | |
104 | client is, in fact, a 4.2 BSD | |
105 | .IR telnet (1C). | |
106 | .PP | |
107 | .I Binary mode | |
108 | has no common interpretation except between similar operating systems | |
109 | (Unix in this case). | |
110 | .PP | |
111 | The terminal type name received from the remote client is converted to | |
112 | lower case. | |
113 | .PP | |
114 | The | |
115 | .I packet | |
116 | interface to the pseudo-terminal | |
117 | (see | |
118 | .IR pty (4)) | |
119 | should be used for more | |
120 | intelligent flushing of input and output queues. | |
121 | .PP | |
122 | .I Telnetd | |
123 | never sends | |
124 | .B TELNET | |
125 | .I go ahead | |
126 | commands. |