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UltraVNC SC doesn't work in a VPN connection

Single Click discussions / bugs
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decibel83
Posts: 7
Joined: 2007-10-03 13:28

UltraVNC SC doesn't work in a VPN connection

Post by decibel83 »

Hi.

I created my personal version of UltraVNC SC.
I use it without any problem every day, but it doesn't work when I try to use it on a VPN connection on the server (the computer which accept the connection from the SC program - the controller computer, not the controlled).
This is a notebook connected to the Internet with an UMTS card and it is also connected with my server (which has a static IP address) with a VPN connection (PPTP).
On the VPN side it has a static IP address (192.168.1.191), so I created on the server a DNAT rule which forwards the incoming calls from the my.public.ip.address:5591 to 192.168.1.191:5500 on the VPN connection.

When I try to connect from UltraVNC SC to my notebook I get the following error on my notebook (the one which has UltraVNC Viewer in listen mode):

Code: Select all

Connection failed - Error reading protocol version
Possible causes:
- You've forgotten to select a DSMPlugin and the Server uses a DSMPlugin
- Viewer and Server are not compatible (they use different RFB protocoles)
- Bad connection
I repeate, the connection work whithout any problem with the same SC program connecting to the same station not connected with a VPN connection, so the problem isn't the DSMPlugin nor the protocols.

What's the problem? Could you help me, please?
I need to make some assistance to my customers when I am out of my office too, using my UMTS card.

Thank you very much!
Bye.
bevtech
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800
Posts: 2168
Joined: 2005-08-03 14:07
Location: Pennsylvania, United States

Re: UltraVNC SC doesn't work in a VPN connection

Post by bevtech »

That would depend on the vpn connection, type of tunnel it is and how it is structured..


I would try to use port 80 or another common port with your single click connection and see if it works.

Need to change the helpdesk.txt ::80 and change the commandline of the listener to -listen 80
Bevtech

Windows XP Home, Pro SP2, Windows 2003 SBS server SP2 (EN), Windows Media Center Editon 2005, Windows Vista Home Premium, Fedora Core 6, Windows 9X, PcHelpWare 1.0, UltraVNC 1.0.8.2

User not developer ;)
redge
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Posts: 6797
Joined: 2004-07-03 17:05
Location: Switzerland - Geneva

Re: UltraVNC SC doesn't work in a VPN connection

Post by redge »

VPN software or hardware ? up to date, fix ?
stack tcp ip need to be smaller for VPN
reduce mtu from 1500 to 1492
UltraVNC 1.0.9.6.1 (built 20110518)
Windows OS: XP Home + Vista Business + 7 Home
Only experienced user, [u]not[/u] developer
decibel83
Posts: 7
Joined: 2007-10-03 13:28

Re: UltraVNC SC doesn't work in a VPN connection

Post by decibel83 »

redge wrote:VPN software or hardware?
VPN software with poptop (pptpd) on Linux Debian.
up to date, fix ?
Yes, it is the latest version available.
stack tcp ip need to be smaller for VPN
reduce mtu from 1500 to 1492
How I can setup it? On the VPN server or the VPN client?

Thank you very much!
redge
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1000
Posts: 6797
Joined: 2004-07-03 17:05
Location: Switzerland - Geneva

Re: UltraVNC SC doesn't work in a VPN connection

Post by redge »

> How I can setup it? On the VPN server or the VPN client?
DrTCP
http://www.dslreports.com/drtcp

at VPN client
UltraVNC 1.0.9.6.1 (built 20110518)
Windows OS: XP Home + Vista Business + 7 Home
Only experienced user, [u]not[/u] developer
decibel83
Posts: 7
Joined: 2007-10-03 13:28

Re: UltraVNC SC doesn't work in a VPN connection

Post by decibel83 »

I changed the MTU to 1492 and 1400 but it doesn't work... :-(
redge
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1000
Posts: 6797
Joined: 2004-07-03 17:05
Location: Switzerland - Geneva

Re: UltraVNC SC doesn't work in a VPN connection

Post by redge »

restart required.
UltraVNC 1.0.9.6.1 (built 20110518)
Windows OS: XP Home + Vista Business + 7 Home
Only experienced user, [u]not[/u] developer
decibel83
Posts: 7
Joined: 2007-10-03 13:28

Re: UltraVNC SC doesn't work in a VPN connection

Post by decibel83 »

Yes, I restarted after any changes I made but it doesn't work...
redge
1000
1000
Posts: 6797
Joined: 2004-07-03 17:05
Location: Switzerland - Geneva

Re: UltraVNC SC doesn't work in a VPN connection

Post by redge »

i'm sorry, out of idea.
UltraVNC 1.0.9.6.1 (built 20110518)
Windows OS: XP Home + Vista Business + 7 Home
Only experienced user, [u]not[/u] developer
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