Go Back   Computer Forums > General Computing > Networking | DNS
Click Here to Login
Join Computer forums Today


Reply
 
Thread Tools Search this Thread Display Modes
 
Old 09-17-2004, 10:38 AM   #1
Beta Member
 
Join Date: Sep 2004
Posts: 3
Question VNC connection over Internet

Hi!

I am trying to connect to a users laptop in Hong Kong from the UK to check setup etc. I am using Real VNC Viewer 4.0 and the user is using the client software. It worked two days ago, but now when I try to connect I get a blank black screen. Nothing has been changed on the client or on my machine. The only thing that has changed is the clients IP address (she is connecting through an ISP over a 6Mb line - dynamic IP address). She has an internet connection, we can contact her via MSN, everything else works except VNC. I've rebooted the client a few times, but still no joy.
I've looked at VNC's website, but this has not thrown anything up that may point to the problem. I've checked the blank/black screen posts on their website, but I don't think this applies as it was working.

Any ideas / suggestions?

Cheers!!
__________________

scouser_steve is offline   Reply With Quote
Old 09-30-2004, 08:42 PM   #2
Beta Member
 
Join Date: Sep 2004
Posts: 3
Default

The server PC has multiple user profiles and is currently logged in to the "wrong" user from the one that you used to set up the vnc connection.

I haven't found a "good" answer, but one person claims that you can disable fast user switchig, and then set up the server under each user to listen on a different port number (log in as usera, set the server to display1, log in as userb, set the server to disply 2, etc... for all users)

then, in the server pc's router where you are currently forwarding port 5900 to their pc, forward the ports for all displays you set up (say, 5900-5905)

after that, there will be a display for each user and all will be black except for the currently active user, if any.

from then on, then from your end in the client you enter not just the ip but the ip and one of the display numbers until you find the one that isn't black, and you'll have to try them all each time you connect since you never know who's using the server pc.

ip:1 or ip:5901 -> usera, black screen, try next...
ip:2 or ip:5902 -> userb, maybe live screen...

I haven't tried this out.

I do know I've used vnc to connect to the login screen of an xp machine before and then select a user and log in as if I were at the pc, but maybe it only worked because I chose the "right" user.

And I have definitely seen the black screen lot's of times and the answer was always to call the remote user up and have them log out all users or all users but the "right" user.

"fast user switching" allows more than one users programs and to stay active in the background at the same time and I have seen it cause problems with many programs that try to launch at start-up and set up a service on a tcp port. Only one process can occupy a given tcp port on the same machine at a time, meaning if usera logs in, and their start-up sets up a server listening on 5900, then uses fast user switching to switch from usera to userb, that process of usera's that's listening on 5900 stays alive still occupying that port. When userb's profile tries to start up the same program, it fails because it can't aquire port 5900. In the case of vncserver, it's easy to have userb's vncserver use some other port that's free, like 5901. But many other programs are not so flexible and all you get is a train wreck.

Unless you disable fast user switching. In that case when usera logs out, all their programs close, meaning when userb logs in, he can use all the same programs and all the same tcp ports.

Hmm, I think I just deduced from above that if you merely disable fast user switching, you shouldn't even have to set up the different display numbers, the one port will work. The different display numbers scheme would be a way to _allow you to keep_ fast user switching, not that it would be even remotely worth the effort for the miniscule gain of having user login/logout go slightly slightly faster...

good luck
__________________

KEYofR is offline   Reply With Quote
Old 10-01-2004, 05:13 AM   #3
Beta Member
 
Join Date: Sep 2004
Posts: 3
Default

The fast user switching doesn't apply as there is only one user. I think it's more to do with dynamic IP adressing from the ISP. A few days after I posted the original question it was working again (because the IP address had luckily reverted to the original IP address). Thanks for your suggestions, but not quite what i was after.
scouser_steve is offline   Reply With Quote
Old 10-01-2004, 01:33 PM   #4
Beta Member
 
Join Date: Sep 2004
Posts: 3
Default

You know I didn't even notice your nick before.
I mostly admin sco boxes all day every day.

If the IP had changed on you, you wouldn't get a black screen, you'd get a failed to connect and never even get a password prompt let alone any type of window.
KEYofR is offline   Reply With Quote
Old 10-03-2004, 06:27 AM   #5
Beta Member
 
Join Date: Sep 2004
Posts: 3
Default

A few crossed wires I think!! scouser is the nickname for a person from Liverpool, and my name is steve, hence scouser_steve.
We did get the connect/password screen and were shown the window with the name of our hongkong PC, but a black screen instead of it's desktop. So as I said, a lot of the stuff on VNC's website doesn't apply. It is working at the moment and has been for about two weeks now which is good - I think now i'm just after info to stop this happpening again - BTW I generally look after Win2K/2K3 stuff.
scouser_steve is offline   Reply With Quote
Old 10-03-2004, 03:08 PM   #6
Beta Member
 
Join Date: Sep 2004
Posts: 3
Default

heh thats funny
KEYofR is offline   Reply With Quote
Old 03-07-2005, 01:43 PM   #7
Beta Member
 
Join Date: Mar 2005
Posts: 1
Default Re: VNC connection over Internet

Hi,

The only way to get your VNC client application working again is to start a Remote Desktop Connection (or Remote Desktops if you have W2K3 server admin tools) to the Windows XP system, open a DOS prompt and type:

TSCON 0 /DEST:console

Your RDC connection will close, (the session will stay opened), and you'll be able to use VNC again.
__________________

Tryptik is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -5. The time now is 01:56 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Friendly URLs by vBSEO 3.6.0