This paper presents the mStar environment, which creates an environment for truly scalable distributed teamwork. It can be and is being used on a daily basis for electronic meetings, distributed electronic education and daily work. It creates a new teamwork environment which allows users to collaborate even if they are not present at the same physical location. The mStar environment includes: the multicast WhiteBoard - mWB, which allows for collaborative reviewing of text and images; mChat, which allows for text based group chat; mVote, which allows for distributed voting and mWeb for shared WWW objects. These are all desktop and IP-multicast based and symmetric. The mStar environment also includes mMOD, which is a VCR-like tool for recording and playback of teamwork sessions, and mTunnel, which is an application for handling IP-multicast traffic on narrow links in the network (such as ISDN/modem) and network segments that does not support IP-multicast.. It allows for scaling and tra...