Re:Bonjour may be what you need. (Score 1)

Try BigAnt Instant Messenger for enterprise , its key features fulfill your requirements: 1. Using a Client/Server architecture and works with intranet, 2. Centralized logging of all conversations; 3. Encrypted data transfer; 4. Not support outside protocols such as AIM, MSN, Yahoo, etc More features: broadcast message, voice and video chat, built-in document management which makes the daily work more efficient and convenient. http://bigantsoft.com/