Connection loss not detected by client

[rob.zietzke@wrsa.com.au]

RealVnc client 4.1.2 on windows XP SP2 connecting to a Solaris Xvnc server 
as follows:

X11vnc server-> firewall ->switch-> router->switch->switch->remote client

If the VNC server is reset, the connection remains half-open, and the 
remote client will show a frozen screen indefinately (up to a couple of 
days)
until the mouse is moved or a key is pressed, then the VNC window dies and 
a popup appears "connection reset by peer, do you wish to reconnect".

Also, if any of the intermediate connections are interrupted, the client 
doesn't timeout the connection.
If the connection resumes again within about 5 mins, then the client 
starts responding again.
If the connection doesn't resume, the remote client will show a frozen 
screen indefinately (as far as I can tell). Using netstat I can see that 
the connection remains "established".
If the mouse is moved, the VNC window dies and the reconnection popup 
appears. (I guess the server socket died, and the mouse update was 
responded with a connection RST).

I want the VNC window to be killed and/or the "reconnection" popup to 
appear after a short timeout if no data is received from the server in all 
cases.
I have tried configuring TCPIP keepalives on the XP client, but this had 
no effect, and no keepalives were observed using Ethereal.
Is there anything else I can do?

Thanks.
Rob