"Joseph A. Knapka" wrote:
>
> Jon Smith wrote:
> >
> > I downloaded your patch for win VNC so that i would be able to use VNC at school
> > (which has a proxy only allowing some ports like port 80) I changed the port
> > setting in the registry to port 80 and i have just tried to access my home computer
> > from school using the java applet through the web page. The java applet loads up
> > fine but when i enter a password it comes back with an error message a couple of
> > minutes later saying somthing like "operation timed out, no connection to host"
>what
> > could be cauusing this? Does the java applet know to use the proxy server of the
> > school?
>
> The Java applet -- aah. Probably doesn't know it has to go through port
> 80 to get to the VNC server. It is probably trying to use 5900 or
> similar.
>
> I will investigate this. It will probably mean adding an option to the
> Java viewer to select which port to connect on.
>
> -- Joe
>
Keep in mind that the Java applet loaded through a HTTP proxy, doesn't
use that proxy with the rfb protocol. So having both http & rfb on port
80 alone doesn't help those who can't use direct TCP/IP connections (or
some kind of transparent proxy), but must use their LAN's HTTP proxy.
(Anyone can test this by telnetting to the rfb host+port)
I have modified the Java viewer to use HTTP proxies (that allow HTTP
CONNECT /SSL) for rfb. The problem for use with LAN HTTP proxies though,
is that the applet must connect to the local HTTP proxy, but Java applet
security prohibits this, because the applet is hosted elsewhere. So the
viewer must be run as an app, or with an appletviewer with adjusted
security settings.
If on the other hand someone is able to make direct connections, but
only on port 80, it's possible to use an outside-the-LAN-HTTP-proxy to
both load the applet and make the rfb connection on port 80. The Java
security problem can be fixed by loading the applet explicitely through
the HTTP proxy (beware: most HTTP proxies don't allow for this though).
Note that this method doesn't need a modified server. Just common
5800/5901 vnc will do. The modified Java client is available on my site.
Anyone with a client-side packet filtering problem can use it with HTML
like this:
APPLET
codebase=http://proxy.spaceproxy.com:80/-_-http://www.workspot.net/~harmen/vnc
code=vncviewer.class archive=vncviewer.jar width=800 height=600
PARAM name=HOST value=[your vnc/rfb server host]
PARAM name=PORT value=5901
PARAM name=PROXYHOST1 value=proxy.spaceproxy.com
PARAM name=PROXYPORT1 value=80
/APPLET
(brackets left out of code not to confuse some mail readers)
For those who must go through their LAN's HTTP proxy there's a bunch of
http-tunnel-tools out there, but it would be ideal in my mind to have a
Java applet do it, becuase you can use it wherever you might happen to
be. Off course this would also require adjustment on the server-side.
Anyway: I will be following your progress with interest: Good Luck!
--
Harmen
Firewall VNC Client: http://www.workspot.net/~harmen/vnc/readme.html
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