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Firewallfriendly Messenger

What's it?

Do you want use ICQ or AOL instant messenger but your company has an paranoid system administrator that blocks nearly every port?

Here't the solution. This little piece of software let's you communicate through the firewall because it uses 100% pure HTML + Java-Applets. Just enter you username and you can send messages to other users, maybe to arrange a chat in a HTML chatroom like

This version contains no password protection, so please be aware that everyboy who nows your username can read your messages. Once you received a message, it will be deleted.

This is an early version, it will change in the future. It is not intended as an full functional chatserver, only a messenger service.

Everything is freeware.


Please type in your nickname in the textfield that appears at startup. Then you can see the applet.

By default, all people that are online are receiving your messages. If you don't want everybody to see what you type, change the state of the 'all' checkbox and mark the receivers you want to send the messages.

The received messages are updated every 3 seconds in the beginning. After some time the rate decreases until you type in a message.

If you want to get informed that somebody send you a message, you can change the value of the 'Alert combo'

Start the Applet

Commandline version

Maybe, you don't want to type in your login name each time you start the program or you don't want to start a webbrowser, then you can run the program as an executable from the commandline.

The program can be run in this way:
java -jar ffm.jar <script location> [nickname [alertmode]]

script location
The location of the script that handles the chat information. If you want to connect to this server, you can type in
The nickname, you want to use. This parameter is optional. If no nickname is passed, you have to type it in at the programs start.
no No alert
silent Alert with a popup dialog
sound Alert with apopup dialog and an alert sound



Applet and Executable

For Programmers

The Chat-Applet consists of two parts. On the client side is the applet that provides the graphical user interface. On the server side is a Perl script that takes the messages to send as a parameter and returns the messages for each user to receive.

In this way, it appears for a firewall as a simple HTML request that will not be blocked. A disadvantage of this method is that the chat parties can't communicate together in a direct connection. So a server is needed and also the chat clients have to poll every few seconds to find out if there are new messages available. This causes a lot of overhead.

Maybe I write a version in the future, that communicates through port 80 between the clients. Don't know why firewalls are so restrictive if workarounds are so easy to program.

Michael Habermann