Re: xwinclip authorisation problem with remote hosts using XDMCP

[Alexander Gottwald <alexander dot gottwald at informatik dot tu-chemnitz dot de>]

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 +127.0.0.1

This is wrong. 127.0.0.1 is the ip adress for localhost. On every computer,
127.0.0.1 points to itself. Say you have a windows host with ip 192.168.26.201
and a unix host with ip 192.168.26.202, they can only communicate with these
ip adresses. Connecting 127.0.0.1 from the windows host will connect to the 
windows host and connecting 127.0.0.1 from the unix host will connect to the 
unix host. 

The correct way is to run xhost windows.host.ip and xwinclip -display 
windows.host.ip:0

> 
> to 127.0.0.1:3.0 broken

Why are you connecting to display 3? this should be 127.0.0.1:0

bye
	ago
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 Alexander.Gottwald@informatik.tu-chemnitz.de 
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