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

["David S. Ahern" <daahern@cisco.com>]

Daniel P. Berrange wrote:
> 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 :-)

It did not kill off established connections for me; it closed the server
socket, but not client connections.

david


> 
>> 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