telnetd(8c)telnetd(8c)Nametelnetd - DARPA TELNET protocol server
Syntax
/etc/telnetd
Description
The server supports the DARPA standard TELNET virtual terminal proto‐
col. The TELNET server is invoked when receives a connection request
on the port indicated in the TELNET service description.
The 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 stdin, stdout, and stderr. The server manipulates
the master side of the pseudo terminal, implementing the TELNET proto‐
col and passing characters between the client and login process.
When a TELNET session is started up, 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.
Aside from this initial setup, the only mode changes will carry out are
those required for echoing characters at the client side of the connec‐
tion.
The 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.
Restrictions
Some TELNET commands are only partially implemented.
The TELNET protocol allows the exchange of the number of lines and col‐
umns on the user's terminal, but does not make use of them.
The terminal type name received from the remote client is converted to
lower case.
The server never sends TELNET go ahead commands.
See Alsotelnet(1c), pty(4), tty(4), services(5), inetd(8c)telnetd(8c)
