UltraVNC

I use SC to support my customers.
Anybody know how i can work if customer use Proxy server or firewall.
which ports i need to open for communication?
I try to use port 80 (-connect 192.168.1.102:80 -noregistry) and sometimes it work.
Thanks, Leonid

Hi. I support customers that use MSaccess application.
Sometimes them report that application work slow or clouser with error (usually when printing large reports).
But when I connect to them with SC application work faster and I cannot see erros.
Somebody have explain this?
Leonid