Additional information:

Winsent Messenger is a messenger for a local network
Winsent Messenger is a program designed for fast messaging and communication in a local network (messenger for a local network). It allows you to organize a convenient and fast exchange of short text messages between individual users of the network and sending messages and alerts to groups of users. The program is designed for use in small and medium-sized local networks of the enterprise, office and home.
Simple and user-friendly interface
WinSent Messenger has a simple but user-friendly user interface. Nothing superfluous, just what you need for comfortable work without unnecessary gestures. The program has a contact list, an archive of messages, a search for users in the local network. Customizable keyboard shortcuts and sound notifications are supported. The program provides a wide range of options to customize the behavior of Winsent Messenger to your needs.
Search and import from Active Directory
The ability to import user accounts from the directory service will help you quickly fill in user groups in the contact list.
Compatible with NET SEND and WinPopup
Winsent Messenger uses the SMB protocol for messaging, which ensures full compatibility with programs such as Microsoft WinPopup, Windows Message Service (net send command), etc. This makes it possible to send and receive messages from those computers on the network on which one of these programs is installed. You will be able to receive messages sent by the system administrator using the net send command, Unix user messages sent by the smbclient command, messages from print spoolers, etc. (More about net send and the message service).
Support for terminal server and the latest versions of Windows
The unique internal architecture allows multiple users to use Winsent Messenger on the teminal server at the same time. The program works in all versions of Windows (2000/XP/Vista/7/8), including Windows 7/8, in which the message service and the net send command are missing. These and the above features allow you to use Winsent as a full-fledged replacement for the message service (net send) and WinPopup.
Does not require a dedicated server and internet connection
Winsent Messenger sends and receives messages in real time, without using intermediate servers. Messages are transmitted directly between users. There is no need to use a dedicated server, third-party services or Internet access. Since Winsent Messenger does not use public unsecured networks (Internet), your data is safe. Messages are transmitted only inside your local network.
Economical use of computer resources
The economical use of computer resources is the result of careful optimization. Winsent Messenger is an extremely compact program - its installation package has a size of about 600 kilobytes. The program works quietly in the background without interfering with your main work.
Free program
Winsent Messenger is a completely free program. Therefore, to make sure of the above, just download and install Winsent. Given the small size of the program, you will not spend a lot of time on this.

Configuring Windows to run WinSent:

The Windows message service is disabled (for Windows NT/2000/XP/2003). It is only necessary if you have installed Winsent Messenger or Winsent Innocenti on your computer. Disabling the message service is not required for the Sent utility to work.
The network interface settings allow the use of "NetBIOS over TCP/IP".
The Windows Firewall allows the exclusion of "File and printer sharing" and the following ports are allowed: UDP ports 137, 138 and TCP ports 139, 445 (for Windows XP/2003/Vista/7).
Network profile settings allow "Network Discovery" and "File and printer sharing" (for Windows Vista/7).
If the above conditions are not met, the program will not function correctly.

Changes in version 2.6:

Fixed: The filter of double broadcast messages does not work correctly.
The default sending timeout value is set to 3500.
Minor fixes and improvements.
Fixed: The program crashes when loading, if the message archive file is corrupted.
Added: UAC dialog when performing actions requiring administrative rights.

Features of the portable version:

The program from the developers does not require installation. It starts and works from any USB media. All data is stored in a folder with a portable program.