In a virtual network computing (VNC) system wherein multiple users, or viewers, at different locations share a common desktop computer for the purpose of sharing control of software applications, the VNCSESSION owner exercises dynamic Internet protocol (IP)-based control over access of the viewers to the server associated with the shared desktop. The VNCSESSION owner is defined as the user who initiates the server and the first viewer to connect to the desktop. The session owner is given full access to the desktop, i.e., active access permitting the viewer to exercise control over the application. For the remaining connected viewers, only VNCVIEWERS having their IP address present in a VNC security file containing authorized IP addresses can initiate activity on the desktop, or exercise control over the application. All other connected viewers may only review desktop activity initiated by other viewers, but cannot initiate such activity themselves, i.e., cannot exercise control over the application. The session owner can dynamically specify, on a per viewer basis as well as on a per session basis, the level of access, passive or active, of each subsequent viewer. The status of each viewer, the number of viewers connected to the desktop from a given IP address, and active/passive selectors for all connected viewers are presented on a video display for review by the session owner.