telnetd.8c

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)telnetd.8c	8.1	9/11/90
.TH telnetd 8c
.SH Name
telnetd \- DARPA TELNET protocol server
.SH Syntax
.B /etc/telnetd
.SH Description
.NXR "telnetd server"
.NXAM "interface" "TELNET user interface" "telnetd server"
.NXS "TELNET protocol server" "telnetd server"
The
.PN telnetd
server supports the DARPA standard TELNET
virtual terminal protocol.  The TELNET server is invoked
when 
.MS inetd 8c  
receives a connection request on
the port indicated in the TELNET service description.
.PP
The
.PN telnetd
server operates by allocating a pseudo-terminal device 
for a client, then creating a login process which has
the slave side of the pseudo-terminal as 
.BR stdin ,
.BR stdout ,
and
.BR stderr .
The
.PN telnetd
server manipulates the master side of the pseudo terminal,
implementing the TELNET protocol and passing characters
between the client and login process.
.PP
When a TELNET session is started up, 
.PN telnetd
sends a TELNET option to the client side indicating
a willingness to do remote echo of characters, to suppress go ahead,
and to receive terminal type information from the remote client.
If the remote client is willing, the remote terminal type is propagated in the
environment of the created login process.
The pseudo terminal allocated to the client is configured
to operate in cooked mode and with XTABS and CRMOD
enabled.
.PP
Aside from this initial setup, the only mode changes
.PN telnetd
will carry out are those required for echoing characters
at the client side of the connection.
.PP
The
.PN telnetd
server supports binary mode, suppress go ahead, echo, and
timing mark. 
It also allows a remote client to do binary, terminal type, and 
suppress go ahead.
.SH Restrictions
Some TELNET commands are only partially implemented.
.PP
The TELNET protocol allows the exchange of the number of lines
and columns on the user's terminal, but
.PN telnetd
does not make use of them.
.PP
The terminal type name received from the remote client is converted
to lower case.
.PP
The
.PN telnetd
server never sends TELNET go ahead commands.
.SH See Also
telnet(1c), pty(4), tty(4), services(5), inetd(8c)