BeeBEEP is the free instant messaging application voted the number 1 in the world by 250,611 professionals who use it every day. BeeBEEP does not need a server to work. This simplicity makes it the best solution available in the world for offices that want to maintain a high level of privacy. BeeBEEP is very easy to use. Install it now on your computer and immediately start exchanging messages and files with your colleagues in a safe and private way.
Not really (LAN Messenger?), all other are discontinued or free proprietary soft. For only file transfer there are Arbore, all others, are proprietary or R.I.P.