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Date: Tue, 28 Mar 2006 10:17:03 +0100
From: "David Picton" <djpicton AT gmail DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Sshd: problem with X11 passthru
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>From: Corinna Vinschen <corinna-cygwin at cygwin dot com>
>To: cygwin at cygwin dot com
>Date: Tue, 28 Mar 2006 09:37:28 +0200
>On Mar 27 18:55, David Picton wrote:
>> I have encountered a problem with the sshd server when the client
>> specifies X11 passthru i.e. ssh -Y or ssh -X.
>>
>> The allocation of virtual displays doesn't work correctly if two or
>> more X11-enabled sessions run at the same time.
>>
>> As I understand it, the server should give each session a unique
>> display number under these circumstances:  localhost:10.0,
>> localhost:11.0, localhost:12.0 etc.
>>
>> Instead, all the sessions have DISPLAY=localhost:10.0 at the same
>> time.  This causes a variety of problems - loss of access to the X
>> server (due to changed Magic Cookie authorization on the server when a
>> new client connects), or the appearance of windows on the wrong server
>> (if two different clients connect).
>>
>> (Note that setting up Magic Cookie authorization on the client machine
>> makes no difference to this bug.  It prevents the client-side warning
>> about 'fake authorization' but it doesn't cure any of the server-side
>> problems!)
>
>I don't see anything Cygwin specific here.  You should ask your
>question on a mailing list or newsgroup dedicated to OpenSSH.
>
>Corinna

Apologies for not making it clear that I was talking about the Cygwin
port of sshd.
The bug seems to be specific to the Cygwin version and I've not seen it on other
systems.

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