MXCONNS(n)            USER COMMANDS              MXCONNS(n)

mxconns - an X11 connection monitor

mxconns [-dispno n] [-hunt] [-verbose]

mxconns is an X11 proxy, i.e, a virtual X11 server (or "display") which can be used as a protective front end for your real X11 server. Each time an X11 application connects to this virtual display, mxconns asks you if the new connection should be accepted. If so, mxconns relays the connection through to your real X11 display.

To use mxconns, start it up on a Unix machine at SLAC with the DISPLAY pointing to your real X11 display, then start all new X11 applications with their DISPLAY pointing to mxconns's virtual display. (See the "Examples" section below.) It's also a good idea to make sure your real display is secured by using "xhost -".

mxconns puts up a small control window which shows all the X11 connections being relayed. Double-clicking on an active connection will close it. Closing the mxconns control window itself will close all the connections and terminate mxconns.

-dispno n
specify the display number of the virtual display to be created; the default is 5. (The display number is the number after the ":" in the standard X11 display name, e.g, the "0" in "". Unlike real display numbers, virtual display numbers usually would not be 0.)
try all virtual display numbers, starting with the value given as -dispno, until an unused number is found.
print the full name of the created virtual display in the same format (hostname:number) that is used by the DISPLAY environment variable; this is useful with the -hunt option.


  1. If you're using an NCD Xterminal at SLAC with a xterm shell window on vesta02, and you want to run a shell at with the display sent back to your NCD:
        vesta02% mxconns -hunt -verbose &
    [The preceding line is a message from mxconns which gives the name of the virtual display that it has created. You will need this information to set the DISPLAY variable on ajax.]
        vesta02% telnet
    [login at ajax, then continue as follows]
        ajax% setenv DISPLAY
        ajax% xterm -name ajax &
    [A dialog box will ask you to OK the connection with]

  2. If you need to open an X application from an OpenVMS machine outside SLAC, first logon to a Unix machine at SLAC. Set the DISPLAY environment variable to point to the machine on your desk and start mxconns on the Unix machine as in Example 1, above. Finally, on the remote OpenVMS machine, set the display as follows (assuming display number 7 on vesta02, as in the previous example):
        $ set display/create/transport=tcpip -
        _$    /
    You will then be able to run your X application.

  3. In a csh or tcsh script, start up mxconns and capture the resulting virtual DISPLAY value to use in a subsequent rsh command:
        set rmtdisplay=`mxconns -hunt -verbose &`
        rsh "xterm -display $rmtdisplay \
            < /dev/null >& /dev/null &"

X(n), xauth(n), xhost(n).

  1. The mxconns control window must not be iconified, otherwise the dialog box for accepting new connections won't appear. (However, it's OK to bury the control window beneath other windows.)

  2. mxconns does not recognize standard X Toolkit options such as -display.

Original code (xconns) by der Mouse (
Motif rewrite by Vaughan Clarkson (
Fixes, extensions and documentation by Lionel Cons (
Minor fixes and modifications by John Halperin (

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This page last revised 27 October 1997.
John Halperin - <>