You can message and share files inside your intranet without a server.
Berty is a secure peer-to-peer messaging app
A universal instant messaging (IM) program
Development toolkit for Web Services and XML data bindings for C & C++
Smoke: Android Crypto Chat Messenger
Cerberus Content Management System
IXSF Messenger is a java-based messenger
Open-source social network CMS and mobile apps.
Create chat bots for Facebook Messenger, Slack, Amazon Alexa, etc.
This Program Contains Many Useful Network Tools
MSN compatible messenger application
Instant Messenger Application
A small (ish) messaging server for anything you can think of
A small, reliable, local network messenger that doesn't need internet
Live chat software to provide online customer support service
simple yahoo messenger client
An intranet chat application that does not require a server.
A messaging system designed for home use Created by: Chad Dunn
Chat Messenger written in Java
A Java RMI base messenger which works on LAN
Underground IM is a free Java Instant Messaging solution.
Mossawir Lan Messenge 3, Sever less Peer 2 Peer Lan messenger