telnetd(8)                          CLIX                          telnetd(8)



  NAME

    telnetd - Runs the TELNET protocol server

  SYNOPSIS

    /usr/ip32/tcpip/telnetd

  DESCRIPTION

    The telnetd server supports the Defense Advanced Research Project Agency
    (DARPA) standard TELNET virtual terminal protocol.  The telnetd server is
    invoked by the Internet server (inetd) normally upon receiving requests to
    connect to the TELNET port as indicated by the /etc/services file (see
    services(4) and inetd(8)).

    The telnetd server operates by allocating a pseudo-terminal device (see
    pty(7)) for a client, and then creating a login process that has the slave
    side of the pseudo-terminal as stdin, stdout, and stderr.  The telnetd
    server manipulates the master side of the pseudo-terminal, implementing
    the TELNET protocol and passing characters between the remote client and
    the login process.

    When a TELNET session is started, the telnetd server sends the following
    TELNET options to the client side, indicating a willingness to:

    ⊕  Perform remote echo of characters

    ⊕  Suppress go ahead

    ⊕  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 a ``cooked'' mode.
    ``Cooked'' mode occurs when all data passed to the pseudo-terminal is
    processed for control characters (such as the <Ctrl-S> and <Ctrl-Q>
    sequences) before data is sent to the buffer.

    The telnetd server can perform in the following modes:

    ⊕  Echo

    ⊕  Binary

    ⊕  Suppress go ahead

    ⊕  Timing mark

    The telnetd server can allow the remote client to perform the following
    modes or task:



  2/94 - Intergraph Corporation                                              1

  telnetd(8)                          CLIX                          telnetd(8)



    ⊕  Binary

    ⊕  Suppress go ahead

    ⊕  Terminal type

  EXAMPLES

    The telnetd server is spawned by the inetd daemon to handle telnet
    connection requests.  The telnetd server is not started as a standalone
    process.

  FILES

    /etc/services
           Service name database.

  NOTES

    Some TELNET commands are only partially implemented.

    The TELNET protocol allows for the exchange of the number of lines and
    columns on the user's terminal, but telnetd does not use them.

    The binary mode has no common interpretation except between similar
    operating systems (CLIX in this case).

    The terminal type name received from the remote client is converted to
    lowercase.

    The packet interface to the pseudo-terminal should be used for intelligent
    flushing of input and output queues (see pty(7)).

    The telnetd server never sends TELNET go ahead commands.

  CAUTIONS

    Because of bugs in the original 4.2 Berkeley Software Distribution (BSD)
    telnet command, telnetd performs some dubious protocol exchanges to
    determine if the remote client is a 4.2 BSD telnet.

  DIAGNOSTICS

    Error messages are displayed if system errors are encountered and are
    prefixed with telnetd:.

  EXIT VALUES

    The telnetd server exits with a nonzero status on error or failure.

  RELATED INFORMATION



  2                                              Intergraph Corporation - 2/94

  telnetd(8)                          CLIX                          telnetd(8)



    Commands:  inetd(8), telnet(1)

    Files:  pty(7), termio(7), services(4)



















































  2/94 - Intergraph Corporation                                              3