xwinclip authorisation problem with remote hosts using XDMCP

Alexander Gottwald alexander.gottwald@informatik.tu-chemnitz.de
Tue Jan 15 00:08:00 GMT 2002

On Tue, 15 Jan 2002, Matthew Donald wrote:

> Hi,
> There is a problem when using xwinclip with an X server which connects to a
> remote host using XDMCP.
> Basically the sequence is this:
> 1.  Execute "XWin :0 -query some.host.system".  Initially, the authorisation
> file contains no records, so the localhost
> has access to the X server by default.  I quote from the Xserver man page:
>     If this file contains  any  authorization  records,  the
>     local  host  is  not  automatically  allowed access to the server, and
> only clients
>     which send one of the authorization records contained in the file in the
> connection
>     setup  information  will be allowed access.
> 2.  XDMCP is used to query some.host.system, which then opens a connection
> to the local PC.  The first
> thing done is that XDMCP adds an auth record for some.host.system  This
> means that localhost loses access
> to the X server.
> 3.  After XWin starts, xwinclip executes on the local host.  It fails with
> the error message: "Could not open display"
> Ok, so I added an xhost command, to explicitly allow access:
>     xhost +

This is wrong. is the ip adress for localhost. On every computer, points to itself. Say you have a windows host with ip
and a unix host with ip, they can only communicate with these
ip adresses. Connecting from the windows host will connect to the 
windows host and connecting from the unix host will connect to the 
unix host. 

The correct way is to run xhost windows.host.ip and xwinclip -display 

> to broken

Why are you connecting to display 3? this should be

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