Web VNC Client Requirements?

[THEIS Jean-Marie 139708]

Hello

There are two cases ( assuming that you uses VNC between two windows stations without having changed port option in the connection menu on VNC server side ) 
* First case using VNC Viewer as client on machine B :
 	Vnc viewer on machine B uses an outgoing connection to the incoming ( and listening ) port 5900 of the VNC server running on machine A . 
 	This means that the firewall protecting machine A must allow incoming connections to port 5900 of machine A.
	This means also that if the firewall protecting machine B filters outgoing connections, it must allow outgoing connections to port 5900 of machine A. 
	All the remaining protocol then happens between B port X and A port 5900.

 * Second case using a Java client on host B ( which then connects to http://HostA:5800 ):
	Http browser of machine B uses an outgoing connection to connects to incoming port 5800 of the VNC server running machine A .
	This port 5800 is used to download the java applet vncviewer.
	Once downloaded, the the java Vnc viewer on machine B uses an outgoing connection to the incoming ( and listening ) port 5900 of the VNC server running on machine A .
	All the remaining protocol then happens between B port X and A port 5900.
	This means that the firewall protecting machine A must allow incoming connections to port 5900 AND 5800 of machine A.
	This means also that if the firewall protecting machine B filters outgoing connections , it must allow outgoing connections to port 5900 AND 5800 of machine A.

***

In both cases port 80 is NOT used at all !!!

Best regards

Hope to help

Jean-Marie Theis

Computers, Network and Data Administration group
Remote Participation technical contact

Commissariat ` l'inergie atomique
Centre de Cadarache
DRFC/STEP  Bt. 506 
13108 Saint-Paul-Lez-Durance Cedex, France 

Til. (phone) : + 33 (0) 4 42 25 77 21 
Fax : + 33 (0) 4 42 25 26 61 
Email : jean-marie.theis "at" cea.fr 

-----Message d'origine-----
De : vnc-list-admin "at" realvnc.com [mailto:vnc-list-admin "at" realvnc.com] De la part de L.M.
Envoyi : lundi 4 juin 2007 11:27
@ : vnc-list "at" realvnc.com
Objet : Web VNC Client Requirements?

Hello,

Suppose the situation is the following:
----------------------------------------------
- running VNC server on host A (network A),
- running VNC client using an "Internet browser"
  and the "Java Runtime Environment" on host B
  (network B).


Problem:
-----------
HOW and WHY host B or its network (network B)
could prevent host B from connecting to the VNC server on host A?
Which could be the reasons?

  - Could the "Java Runtime Environment" be responsible for that?
  - Could it be because the VNC client on host B uses ports other
    than port 80 to communicate with the VNC server on host A?
    (Does the client also uses ports 5800 and 5900?)
  - In other words, are there any requirements on the client other
    than having an "Internet browser" and a "Java Runtime Environment"
    available?

I am only interested on the client side of the communication
(suppose everything is OK on the server side: no firewall, etc.).

Please help!

Thanks in advance,

--
Leon
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