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Network Working Group J. Postel Request for Comments: 861 J. Reynolds

                                                                   ISI

Obsoletes: NIC 16239 May 1983

               TELNET EXTENDED OPTIONS - LIST OPTION

This RFC specifies a standard for the ARPA Internet community. Hosts on the ARPA Internet are expected to adopt and implement this standard.

1. Command Name and Code

 EXTENDED-OPTIONS-LIST (EXOPL)     255

2. Command Meanings

 IAC DO EXOPL

    The sender of this command REQUESTS that the receiver of this
    command begin negotiating, or confirms that the receiver of this
    command is expected to begin negotiating, TELNET options which are
    on the "Extended Options List".

 IAC WILL EXOPL

    The sender of this command requests permission to begin
    negotiating, or confirms that it will begin negotiating, TELNET
    options which are on the "Extended Options List".

 IAC WON'T EXOPL

    The sender of this command REFUSES to negotiate, or to continue
    negotiating, options on the "Extended Options List".

 IAC DON'T EXOPL

    The sender of this command DEMANDS that the receiver conduct no
    further negotiation of options on the "Extended Options List".

 IAC SB EXOPL <subcommand>

    The subcommand contains information required for the negotiation
    of an option of the "Extended Options List".  The format of the
    subcommand is discussed in section 5 below.

3. Default

 WON'T EXOPL, DON'T EXOPL

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RFC 861 May 1983

    Negotiation of options on the "Extended Options List" is not
    permitted.

4. Motivation for the Option

 Eventually, a 257th TELNET option will be needed.  This option will
 extend the option list for another 256 options in a manner which is
 easy to implement.  The option is proposed now, rather than later
 (probably much later), in order to reserve the option number (255).

5. An Abstract Description of the Option

 The EXOPL option has five subcommand codes:  WILL, WON'T, DO, DON'T,
 and SB.  They have exactly the same meanings as the TELNET commands
 with the same names, and are used in exactly the same way.  For
 consistency, these subcommand codes will have the same values as the
 TELNET command codes (250-254).  Thus, the format for negotiating a
 specific option on the "Extended Options List" (once both parties
 have agreed to use it) is:

    IAC SB EXOPL DO/DON'T/WILL/WON'T/<option code> IAC SE

 Once both sides have agreed to use the specific option specified by
 <option code>, subnegotiation may be required.  In this case the
 format to be used is:

    IAC SB EXOPL SB <option code> <parameters> SE IAC SE

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