Network Working Group                                           G. Marcy
Request for Comments: 1096                    Carnegie Mellon University
                                                              March 1989
 
 
                    Telnet X Display Location Option
 
Status of This Memo
 
   This RFC specifies a standard for the Internet community.  Hosts on
   the Internet that transmit the X display location within the Telnet
   protocol are expected to adopt and implement this standard.
   Distribution of this memo is unlimited.
 
   This standard is modelled on RFC 1079 [1], the telnet terminal speed
   option.  Much of the text of this document is copied from that RFC.
 
Motivation
 
   When a user is running the Telnet client under the X window system,
   it is useful for the remote Telnet to know the X display location of
   that client.  For example, the user might wish to start other X
   applications from the remote host using the same display location as
   the Telnet client.  The purpose of this option is to make this
   information available through telnet connections.
 
1. Command Name and Code
 
      X-DISPLAY-LOCATION (XDISPLOC)
 
      Code = 35
 
2. Command Meanings
 
      IAC WILL X-DISPLAY-LOCATION
 
         Sender is willing to send the X display location in a
         subsequent sub-negotiation.
 
      IAC WON'T X-DISPLAY-LOCATION
 
         Sender refuses to send the X display location.
 
      IAC DO X-DISPLAY-LOCATION
 
         Sender is willing to receive the X display location in a
         subsequent sub-negotiation.
 
 
 
 
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RFC 1096            Telnet X Display Location Option          March 1989
 
 
      IAC DON'T X-DISPLAY-LOCATION
 
         Sender refuses to accept the X display location.
 
      IAC SB X-DISPLAY-LOCATION SEND IAC SE
 
         Sender requests receiver to transmit his (the receiver's) X
         display location.  The code for SEND is 1.  (See below.)
 
      IAC SB X-DISPLAY-LOCATION IS ... IAC SE
 
         Sender is stating his X display location.  The code for IS is
         0.  (See below.)
 
3. Default
 
      WON'T X-DISPLAY-LOCATION
 
         The X display location will not be exchanged.
 
      DON'T X-DISPLAY-LOCATION
 
         The X display location will not be exchanged.
 
4. Description of the Option
 
   WILL and DO are used only to obtain and grant permission for future
   discussion.  The actual exchange of status information occurs within
   option subcommands (IAC SB X-DISPLAY-LOCATION...).
 
   Once the two hosts have exchanged a WILL and a DO, the sender of the
   DO X-DISPLAY-LOCATION is free to request the X display location.
   Only the sender of the DO may send requests (IAC SB X-DISPLAY-
   LOCATION SEND IAC SE) and only the sender of the WILL may transmit
   actual X display location (within an IAC SB X-DISPLAY-LOCATION IS ...
   IAC SE command).  The X display location may not be sent
   spontaneously, but only in response to a request.
 
   The X display location is an NVT ASCII string.  This string follows
   the normal Unix convention used for the DISPLAY environment variable,
   e.g.,
 
         <host>:<dispnum>[.<screennum>]
 
   No extraneous characters such as spaces may be included.
 
      The following is an example of use of the option:
 
 
 
 
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RFC 1096            Telnet X Display Location Option          March 1989
 
 
         Host1: IAC DO X-DISPLAY-LOCATION
 
         Host2: IAC WILL X-DISPLAY-LOCATION
 
      (Host1 is now free to request status information at any time.)
 
         Host1: IAC SB X-DISPLAY-LOCATION SEND IAC SE
 
         Host2: IAC SB X-DISPLAY-LOCATION IS "SRI-NIC.ARPA:0.0" IAC SE
 
      (This command is 22 octets.)
 
5. Implementation Suggestions
 
   Since the X display location may not contain a hostname on the client
   host, i.e., ":0" or "unix:0.0", the Telnet client will need to modify
   the location appropriately before sending it on to the remote Telnet.
 
Reference
 
   [1]  Hedrick, C., "Telnet Terminal Speed Option", RFC 1079,
        Rutgers University, December, 1988.
 
Author's Address:
 
   Glenn A. Marcy
   Carnegie Mellon University
   School of Computer Science
   Pittsburgh, PA 15213-3890
 
   Phone: (412) 268-7669
 
   Email: Glenn.Marcy@CS.CMU.EDU
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Marcy                                                           [Page 3]