I am trying to use krdc on the client with x11vnc on the server. If I connect with high resolution, it works. If I try low or medium, I get a message that "the connection to the host has been interrupted". I don't see anything in the x11vnc log to hint of why the connection is being dropped.

Any thoughts?

(x11vnc is running on my debian box)

i read this on the x11vnc page, http://www.karlrunge.com/x11vnc/

"No problems like this have been observed with Windows VNC Viewers: they all seem to keep their entire framebuffer in local memory. Gotcha for KDE krdc VNC Viewer: One user found that KDE's krdc viewer has some sort of hardwired limit on the maximum size of the framebuffer (64MB?). It fails quickly saying "The connection to the host has been interrupted." The workaround for his 1280x1024 x11vnc-side display was to run with "-ncache 10", i.e. a smaller value to be under the krdc threshold."

however i don't find ncache as an option in my x11vnc... so i still have this problem, but it only occurs when i don't use the high quality setting on krdc

You might be seeing this bug: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=399408

It is fixed upstream. What version of x11vnc are you using?