Re: [Qemu-devel] resetting a stale VNC connection

[Daniel P. Berrange]

On Tue, Apr 21, 2009 at 11:49:11AM -0500, Anthony Liguori wrote:
> Daniel P. Berrange wrote:
> >On Tue, Apr 21, 2009 at 04:38:55PM +0300, Avi Kivity wrote:
> >  
> >>David S. Ahern wrote:
> >>    
> >>>Is there a monitor command (or other method) to force a VNC client
> >>>connection to close?
> >>>
> >>>It looks like the vnc code does not use keepalive probes. If the
> >>>connection is left hanging the VNC server will never drop it. I have hit
> >>>this condition a couple of times when a VPN connection drops while the
> >>>vncviewer is connected to a VM.
> >>>
> >>>Specific software version at the moment is kvm-81.
> >>> 
> >>>      
> >>Why not just enable tcp keepalives?
> >>    
> >
> >Independant of killing off stale VNC clients, it could be desirable to
> >have a monitor command to kill a client, to allow revoking of end user
> >access to VNC.
> >  
> 
> I'm surprised change vnc none doesn't kill off all VNC connections.

It may well do that - i've not tried it :-)

> I don't see a compelling use case to boot off individual clients other 
> than we can.  Is there something specific you were thinking someone 
> would want to do?

I've no pressing need for this - i was just thinking of possible use
cases for the command. Now we allow multiple concurrent VNC clients, and
can authenticate them, I just thought that it might be desirable to be
able to drop individual authenticated clients. eg if you've revoked
their credentials, but they still have a session open. Turning off+on
the whole VNC server would work as a big stick too.

Daniel
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