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. Marcy [Page 1] 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: Marcy [Page 2] 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: [email protected]
Marcy [Page 3]