UVNC goes bad, remote reboot won't clear, switchoff needed

[pol098]

I have a problem with an Ultravnc connection which goes bad after a while and can't be reinstated by remote rebooting. Both machines running Windows XP 32-bit patched up to date, UltraVNC 1.0.8.2 as service, same version viewer.

Basically the server goes unresponsive and a connection can't be made. The machines remain networked, & files on the server can be accessed from the viewer machine (but not via VNC). Physically switching off and restarting the server clears the problem. However, hibernating the remote machine, or restarting it, or switching it off remotely (all via Windows XP Computer Management from Administrative Tools), then waking it up with WoL allows file access, but a VNC connection always fails with socket error 10061 reported in the log until the machine is physically switched off. This is a problem if the remote and server are on different continents, as happens.

More details (repeating some of the above):
This is a system using Wake on LAN (WoL). The host machine is set to hibernate after 60 minutes of non-use. The remote machine can wake it up (from the same LAN by running any wake-up program; from anywhere else with an Internet connection by using router facilities). This generally works very well.

Occasionally something happens to the UltraVNC server on the host machine; it wakes up successfully, confirmed by being able to transfer files between machines (a stronger test than a ping), but a local vncviewer can't connect. Given a network connection, it's possible to hibernate, restart, or shutdown the server from the remote, and wake it with WoL. This is always successful (network connection is reestablished), but a VNC connection can't be made in spite of the shutdown. Simply walking over to the server (if not too far away) and switching it off and back on again with the power switch clears the problem, but is no good for reliable unattended operation.

It's almost certainly not a hibernation issue, as restarting should clear such things.

Server hardware is a rather old Gigabyte Pentium 4 GA-8KNXP motherboard with 4GB, not overclocked, very stable.

The vncviewer log (level 10) is just:

Started and Winsock (v 2) initialised
bufsize expanded to 4352
Registered connection with app
Clipboard changed
Don't send initial clipboard!
socket error 10061
Deregistered connection from app
Exiting
VNC viewer closing down

Does anybody have any ideas on the cause and solution?

Bdest wishes, pol098

[B]

Not really... but taking WOL out of the picture, are you saying that soft restart does NOT allow VNC connections, but a physical restart does? And yet every other network utility besides VNC works after the soft restart?

That's odd... perhaps there's something you can set in the BIOS to flush the NIC's buffers upon a soft restart?

[pol098]

Sorry about the delay - back for the moment, but unable to make VNC connections which I had done on past occasions. My original description is probably incorrect; I suspect that someone on-site may have have run UltraVNC as a program after the server was rebooted. What is happening is that the connection does sometimes go bad, but on rebooting the service does not start properly - this is discussed by others in another thread, several people report that VNC hasn't been working when started as a service; the service is listed as running but there is no WinVNC system tray icon and viewers can't connect. The VNC connection going bad is not too serious a problem if the machines are still networked, as a remote reboot would clear the problem: but only if the VNC service starts! The whole system worked beautifully in the past (last successful serious use Nov 09); the problems may be connected with more recent changes to uvnc, or Win XP updates. Basically the whole remote unattended system has stopped being usable reliably, though it worked fine on the same hardware and OS. I mentioned WoL for completeness; it works and is not part of this problem. Best wishes, pol098