Mark, You can enable debug output from VNC Viewer either to a console window with:
Vncviewer -console -log=*:stderr:100 Or to C:\temp\vncviewer4.log with: Vncviewer -log=*:file:100 (You'll need to ensure that C:\temp exists and is writable) Cheers, Wez @ RealVNC Ltd. > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Mark > Sent: 09 June 2005 13:59 > To: [email protected] > Cc: [EMAIL PROTECTED]; [EMAIL PROTECTED]; [EMAIL PROTECTED] > Subject: Re: Screen freezing in VNC4.1.1 over SSH > > Oops, must have hit reply rather than reply all to my last message... > > ---------- Forwarded message ---------- > From: Mark <[EMAIL PROTECTED]> > Date: Jun 8, 2005 6:40 PM > Subject: Re: Screen freezing in VNC4.1.1 over SSH > To: James Weatherall <[EMAIL PROTECTED]> > > > Wez, > > Thanks - I'll try running vncserver in debug mode and see if that > suggests anything. How do I get debugging turned on? I have added > DebugLevel and DebugMode DWORD keys to HKLM\Software\RealVNC\WinVNC4 > (12 and 2 decimal respectively) and rebooted the machine, but I can't > find any winvnc.log file (and did a file search just to make sure). > I've also tried on another machine with VNC server in user mode and > can't get that working either (with 2, 4, or 6 in the DebugMode key). > Sorry if I am missing something obvious. > > Re my comment on the timer: > To help figure out what happens when I have a simple batch script > running which loops endlessly and prints the time to a terminal > window. When running it will just show the time scrolling up the > terminal window endlessly. > > When I unminimize VNC the screen updates and time appears to scroll up > for a very short time before the window freezes. In other words, had > the session frozen while VNC was minimised I would expect to see the > time that the session froze as some time before I unminimised. > However, what I always see is that very brief update and the freezing > with the time showing the current time when I unminimised - so it > would appear that the act of unminimising is triggering something > which causes the session to freeze. > > On 6/8/05, James Weatherall <[EMAIL PROTECTED]> wrote: > > Mark, > > > > I'd recommend running VNC Viewer with full debugging > enabled, to see if it > > reports any useful information. > > > > Since you don't see the problem when using VNC without SSH, > it does seem > > likely that something is amiss with your SSH tunnels. > > > > I'm not sure I understand your timer comment, but it is > often the case that > > VNC Viewer will not detect that a connection has dropped > when minimized, > > until it is restored, since it doesn't request updates or > send input events > > to the server when minimized and those are how it detects > dead links. > > > > Regards, > > > > Wez @ RealVNC Ltd. > > > > > > > -----Original Message----- > > > From: Mark [mailto:[EMAIL PROTECTED] > > > Sent: 08 June 2005 17:26 > > > To: Collins, Kevin (MindWorks) > > > Cc: James Weatherall; Andy Bruce - softwareAB; > [email protected] > > > Subject: Re: Screen freezing in VNC4.1.1 over SSH > > > > > > Kevin - CPU time in vncviewer remains at zero while > active and once > > > frozen. CPU usage is very low all the time, only > occasionally flicking > > > up to 1 or 2 %, unless I move the VNC window around in > which case it > > > goes up, and then (eventually) CPU time does increment. > > > > > > While looking at this, VNC viewer quit (after session was frozen) > > > without warning or error, and this did give SSH errors > relating to a > > > session unexpectedly closing, which makes sense. > > > > > > Wez - I don't think SSH timing out is causing the problem: > > > * no errors in SSH log prior to VNC session freezing > > > * session freezing is mostly triggered by my brining > VNCviewer out of > > > a minimised state (when I do this the timer I have > running continues > > > to update for <<1 second before freezing, so it would > appear that all > > > is OK with the session until I unminimize VNCviewer) > > > * the VNC server error always happens about 30 after the freeze > > > > > > That said, I there is certainly something going on > between VNC and SSH > > > as I have never seen this if I run VNC in the clear. > > > > > > mark. > > > > > > On 6/8/05, Collins, Kevin (MindWorks) > > > <[EMAIL PROTECTED]> wrote: > > > > Wez, > > > > > > > > is it possible this is related to the "hang" (in > actuality, > > > > looping) that I have been working with you on? > > > > > > > > Mark - if you look at the Windows task manager, under the > > > "Processes" > > > > tab, is the vncviewer process "CPU Time" value incrementing? > > > > > > > > Kevin > > > > > > > > -----Original Message----- > > > > From: [EMAIL PROTECTED] > > > [mailto:[EMAIL PROTECTED] On > > > > Behalf Of James Weatherall > > > > Sent: Wednesday, June 08, 2005 7:24 AM > > > > To: 'Mark'; 'Andy Bruce - softwareAB' > > > > Cc: [email protected] > > > > Subject: RE: Screen freezing in VNC4.1.1 over SSH > > > > > > > > > > > > Mark, > > > > > > > > I think Andy is suggesting that the problem is SSH > timing out the > > > > tunnelled > > > > connection - this theory is supported by the fact that the > > > server sees > > > > the > > > > connection drop. > > > > VNC clearly isn't causing any network problems, since > you can still > > > > interact > > > > with the SSH session. > > > > > > > > Cheers, > > > > > > > > Wez @ RealVNC Ltd. > > > > > > > > > > > > > -----Original Message----- > > > > > From: [EMAIL PROTECTED] > > > > > [mailto:[EMAIL PROTECTED] On Behalf Of Mark > > > > > Sent: 08 June 2005 14:35 > > > > > To: Andy Bruce - softwareAB > > > > > Cc: [email protected] > > > > > Subject: Re: Screen freezing in VNC4.1.1 over SSH > > > > > > > > > > Thanks Andy. > > > > > > > > > > It may be something in the network which is causing > VNC to freeze, > > > > > however if that is the case then VNC appears to be > > > causing the network > > > > > problem. My rationale is that the freeze mostly happens > > > immediately > > > > > after I bring the VNC window to the foreground. Also, the > > > if I set a > > > > > ping going on the SSH terminal session, it keeps going > > > without problem > > > > > during and after the freeze. > > > > > > > > > > Either way, your suggestion of getting debug info from > > > SSH is a good > > > > > one - I'll report back when I've got some info from that. > > > > > > > > > > mark. > > > > > > > > > > On 6/8/05, Andy Bruce - softwareAB > <[EMAIL PROTECTED]> wrote: > > > > > > I think you are confusing SSH timeouts (which I get > > > > > sporadically myself > > > > > > when connecting to my business LAN) with the VNC > freeze. In my > > > > > > experience, the VNC freeze only occurs when the > > > underlying network > > > > > > connection itself hangs. Although it may appear that > > > the problem is > > > > > > VNC-related (since you can start another session > > > presumably without > > > > > > restarting your SSH tunnelling client), the symptom you > > > > > report happens > > > > > > only when there is a problem with the underlying network > > > > > connection. VNC > > > > > > is simply the innocent consumer of that connection. > > > > > > > > > > > > As far as I know, the only solution to your problem is to > > > > > work thru the > > > > > > SSH connectivity problems. I have one Windows-based client > > > > > company who > > > > > > has allowed the single port 22 to be opened (specifically > > > > > for my use in > > > > > > fact) since they do not wish to give me corporate VPN > > > access. As I > > > > > > mentioned above, that particular connection times out, > > > > > freezes up, and > > > > > > does other strange things which their "normal" VPN > > > > > connection does not > > > > > > do. You're in luck since you appear to have some > > > control over your > > > > > > connection to the remote Linux box; I suggest that you turn > > > > > on debugging > > > > > > on the SSH daemon on that box to get detailed information > > > > > about what's > > > > > > going on. In my case, the network folks (all M$NE > certified, and > > > > > > therefore useless for any real work) simply shrug their > > > > > shoulders and > > > > > > brush me off. > > > > > > > > > > > > Good luck, > > > > > > > > > > > > Andy > > > > > > > > > > > > Mark wrote: > > > > > > > > > > > > >I have been having problems with sessions hanging when > > > running VNC > > > > > > >over SSH. I will have a session open, and after some > > > time find that > > > > > > >the screen has frozen. Refreshing the screen doesn't help, > > > > > however if > > > > > > >I close the session I can open another one just fine > > > > > (though it seems > > > > > > >to take a few seconds longer to reconnect than it did > > > originally). > > > > > > >This happens in the following circumstances: > > > > > > > > > > > > > >* if I minimize the VNC session window for about 15 or > > > > > more minutes, > > > > > > >the session always freezes immediately after I > > > maximize (I have a > > > > > > >batch file printing the time continually and the time is > > > > > current when > > > > > > >I maximise, but does not continue to update). If I > > > > > minimise and then > > > > > > >maximise after a couple of minutes, the session does not > > > > > freeze. If I > > > > > > >maximise between 2 and 15 minutes the session > sometimes freezes > > > > > > >(almost always after 5 minutes). > > > > > > >* if the session is not minimised but just in the > > > background, the > > > > > > >session usually freezes but after a more variable and > > > > > longer length of > > > > > > >time. > > > > > > >* sometimes the session freezes when I am using it > > > actively. Again, > > > > > > >length of time is variable. > > > > > > > > > > > > > >The setup I am using is as follows: > > > > > > > > > > > > > >VNC Client (RealVNC Free 4.1.1) on Win XP Pro > > > > > > >| > > > > > > >Linux firewall running NAT > > > > > > >| > > > > > > >ADSL Router running NAT > > > > > > >| > > > > > > >| > > > > > > >ADSL Router running NAT > > > > > > >| > > > > > > >Linux Firewall running NAT & OpenSSHd > > > > > > >| > > > > > > >Remote machine (RealVNC Free 4.1.1 server) on Win XP Pro > > > > > > >-session timeout set to 60000 seconds > > > > > > > > > > > > > >The only port open on the remote Linux firewall is 22, and > > > > > I set up a > > > > > > >SSH tunnel from local client (with PuTTY) to the > remote Linux > > > > > > >Firewall, which then forwards VNC traffic to the > > > remote VNC server. > > > > > > > > > > > > > >I don't see any problem with the SSH session when the > > > VNC session > > > > > > >hangs (nothing in the SSH log, SSH terminal session is > > > > > fine). I have > > > > > > >also reproduced the problem connecting from different PCs. > > > > > > > > > > > > > >I do get an entry in the Windows event log of the > VNC server > > > > > > >(connection reset by peer 10054), but this entry is logged > > > > > after the > > > > > > >time session froze, so presumably it is a result of the > > > > > freeze not the > > > > > > >cause? > > > > > > > > > > > > > >If I put the remote machine in front of the Linux firewall > > > > > (ie just in > > > > > > >ADSL router NAT) and connect directly (ie no SSH > tunnel) the > > > > > > >connection is stable and does not hang. > > > > > > > > > > > > > >Any assistance in fixing this would be most appreciated. > > > > > > > > > > > > > >thanks > > > > > > > > > > > > > >mark. > > > > > > >_______________________________________________ > > > > > > >VNC-List mailing list > > > > > > >[email protected] > > > > > > >To remove yourself from the list visit: > > > > > > >http://www.realvnc.com/mailman/listinfo/vnc-list > > > > > _______________________________________________ > > > > > VNC-List mailing list > > > > > [email protected] > > > > > To remove yourself from the list visit: > > > > > http://www.realvnc.com/mailman/listinfo/vnc-list > > > > _______________________________________________ > > > > VNC-List mailing list > > > > [email protected] > > > > To remove yourself from the list visit: > > > > http://www.realvnc.com/mailman/listinfo/vnc-list > _______________________________________________ > VNC-List mailing list > [email protected] > To remove yourself from the list visit: > http://www.realvnc.com/mailman/listinfo/vnc-list _______________________________________________ VNC-List mailing list [email protected] To remove yourself from the list visit: http://www.realvnc.com/mailman/listinfo/vnc-list
