One of alternatives is Sofros LAN messenger.
Pros: It supports Terminal Services (great for large networks) All messages are encrypted by secure algorithm, it sends messages to offline users.
Cons :Application has 30 days full functional trial
- Simple user interface
- online/offline/busy status
- Net send command doesn't work in latest Windows Systems. Softros works between XP, Vista, 7,8, 8.1
- Full version is about $12.95 per copy
