Member Avatar for evman

Good morning lads!

Just stumbled across this site (think it was one of the top matches in Google when I searched for how to consistently show the solutions on EE without signing up :P)

But what I was searching for on there, and what I will ask on here is:

Does anyone know of a free LAN messaging program that can work as a one-way alerter? (For Windows XP Workstations)

Hopefully, I could simply install as a service on 'client' machines that waits until a message gets sent to it from the 'server' machine, then it displays a popup with the message (broadcast messages most often, like "Server down at 6pm"). I've been poking around the last few weeks, have trialled AChat, IPMsg, and various others. They all seem to work to a degree, but I really need a program that only offers one-way-communication, or an option somewhere to configure it as such. (Else, users will probably play around with and misuse the software).

I've only been able to find free software that does WAY too much and will hook the workplace up with a virtual chat room to waste time in, or software that does exactly what I'm after, yet wants to charge me for it (though, it has LESS features than these open source programs… I guess they know their target market :P)

Ideally, I'd like something with no icons/system tray indicator. Just something humming along silently in the background, listening on its port. The less the user knows they can fiddle with, the better.

The 'server' portion of the program will need to be able to broadcast to all users on a subnet, and be able to broadcast to other subnets… Oh, and I really DON'T want a program that relies on the "Messenger Service" running. For one, 'net send' doesn't like to transverse subnets. There's a company firewall set up obviously, but I'm still not a fan of the security risk I'd open up, at least internally.

LanInfoXP and Bopup Observer would be likely candidates, if my endeavour was funded :P

Has anybody stumbled across anything like this in their travels? It's such a simple concept, but I've had next to no luck in finding a tool to suit my needs.

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  • Latest Post Latest Post by Ipan_1

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Generated

Quick summary and practical follow-ups based on the thread: found a small utility (the “MessageSendApp” he linked) that does exactly the one‑way alert job but required .NET 2.0 and only broadcasts on the local subnet; confirmed it worked; later asked for the link, which may no longer be available. For readers arriving years later: the pattern here (a silent client + single server broadcaster) is simple and reliable, but there are a few deployment and network realities that weren’t fully discussed in the replies.

Key deployment notes and a minimal implementation route

  • Routers do not forward Layer‑2 broadcasts between subnets, so a broadcast‑only server won’t reach other subnets. Two practical choices: install a tiny relay/agent in each subnet (the agent receives a unicast from the central server or subscribes to a multicast group) or have the server iterate a maintained list of host IPs and send unicast alerts.
  • Avoid relying on the old Windows Messenger Service / net send — it’s often disabled and unreliable across routed networks.
  • To keep the client invisible to users: run it as a Windows service with a simple config file (port, log path, allowed-senders). Sign the binary and get it whitelisted with AV/endpoint tools to reduce false positives.

Simple proof-of-concept (shows the idea; package or compile for production)

# minimal Python UDP listener (popup on receive)
import socket, ctypes
PORT = 9999
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM); s.bind(('', PORT))
while True:
    data, addr = s.recvfrom(4096)
    ctypes.windll.user32.MessageBoxW(0, data.decode('utf-8','replace'), "Alert", 0)

Package into a single executable (pyinstaller/py2exe) or rewrite in C/Go for a zero‑runtime binary.

Troubleshooting & hardening checklist

  • Open the chosen UDP/TCP port in host firewalls; test with netcat/Wireshark.
  • Log every alert to Event Log for auditing.
  • Use a simple message signature/hmac if there’s any risk of spoofing.
  • Coordinate with security/AV teams before wide rollout (silent agents can trigger alerts).

If the original link is gone, the fastest path is either to rebuild a tiny agent like the example above and deploy via Group Policy/PSExec, or run a small per‑subnet relay so cross‑subnet delivery is deterministic.

Member Avatar for evman

As an update, I've discovered a small program someone made which pretty much does what I need. (There's 2 exe's. One which is the 'server', for sending the messages, and the other which installs itself as a client, hidden away and running in the background.) Only shortcoming is it's non-configurable (will only broadcast to current subnet) and it requires .NET 2.0 framework to be installed. Given that I'll need this 'messenger' to be on 200+ PCs, that'll make this a more arduous task than I'm hoping…

So yea, I'm definitely still looking, if someone's come across anything that's worth me checking out!

Member Avatar for charlieton

As an update, I've discovered a small program someone made which pretty much does what I need. (There's 2 exe's. One which is the 'server', for sending the messages, and the other which installs itself as a client, hidden away and running in the background.) Only shortcoming is it's non-configurable (will only broadcast to current subnet) and it requires .NET 2.0 framework to be installed. Given that I'll need this 'messenger' to be on 200+ PCs, that'll make this a more arduous task than I'm hoping…

So yea, I'm definitely still looking, if someone's come across anything that's worth me checking out!

Hey, what was the name of this program? ty

Member Avatar for evman

Hey, what was the name of this program? ty

I'm not sure if it's really called anything other than "MessageSendApp" Pretty basic eh? :P

Download it at:

DedDerek from the www.whirlpool.net.au forums hooked me up with the program, and the following information:
"A few notes:
- This software was written very quickly so may still have some bugs in it. WhIM me if you find something wrong with it that you would like fixed.
- Messages will only be sent to computers on the same local network as the server program. The messages will not go through firewalls or over the internet.
- I hope its self explanatory enough for you. The client program especially has no interface so to close it you need to end it from Task Manager

Enjoy,
Derek :)"

Full props to Derek... the program almost does exactly what I need. Just the .NET prerequisite makes it a little less appealing.

Member Avatar for charlieton

OMG!!! PROPs to both of you guys. uneffing believable. i've been looking for something like this for at least a year.

It works. small foot print. amazazazing!!!

thank-you so much!!!

Member Avatar for Ipan_1

Please give me again link url , because the link url link up there is not valid anymore. Thanks

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