Bopup Communication Server is a corporate solution for instant messaging and Network Groups management over a local area network. Bopup Communication Server includes Message Manager and Group Manager. Group Manager provides control and management of Network Groups. Message Manager lets store messages on the server and automatically forward them to recipients on the network. Bopup Communication Server will be useful for large networks with large number of Network Groups, computers and users. It requires no assistance for remote users. All operations for creating and deleting groups, assigning and removing users to/from groups, saving messages on the server are transparent to network users. Bopup Messenger, Bopup Secure Messenger and Bopup Observer automatically receive Network Groups, that are currently assigned to them, and all messages, that were sent offline.