Will be setting up a site for a not-for-profit organization shortly, probably using Debian on a PC.

One of the requirements is to allow members to communicate among themselves anonymously, (without members finding out other members e-mail addresses which will be kept on our database).

For example if our member with E-mail address anthony@this_ip.com.zz
wants to communicate with our member with E-mail address
annemarie@another_ip.net.aa, we will have both E-mail addresses on our database but we have to find a way to allow anthony and annemarie to
communicate with one another without becoming aware of the other's
E-mail address.

We'd like also to free our computer once this communication is established,
if we can.

What would be the most efficient way to do this?

A big thank you to those who answer these questions.

the best way to do it would be a PHP/MySQL web chat app. You can find some examples of it on the net (google) or in http://sourceforge.net/

Merci beaucoup Pedro, je passerai probablement les prochaines semaines pour me familiariser ou apprendre comment utiliser ton conseil.

Blampain

your wellcome!

start with (of course):

PHP
http://fr2.php.net/docs.php

MySQL
http://www.mysql.com/

Apache
http://httpd.apache.org/

PHP editor for windows and linux:
http://www.scintilla.org/SciTE.html

some usefull database tools:
http://www.dbtools.com.br/
http://www.fabforce.net/dbdesigner4/

other info:
http://www.kitebird.com/articles/access-migrate.html
good book from O'reilly:
http://oreilly.free.fr/mysqlphp/
http://www.hotscripts.com/
http://www.phpbuilder.com/columns/alberto20000919.php3
http://www.unixodbc.org/doc/UserManual/

If your clients communicate directly some identifying info will get through (ie IP address). You'll want your server in the middle to act as a proxy. Did you want real time communications like IM? If yes, you'll want a system that uses a central server that accepts the message and forwards them to the appropriate client. Something like Jabber might do the trick. You could also go the web-based route. You can find several collaboration packages over at Freshmeat.

You could also use a web mail system that assigns each user an e-mail address @yourdomain.tld. Your database can associate their outside e-mail address with the one in your database and accept the messages, then re-write the header to use the e-mail address from your organization before sending to the intended destination. Only your system will know the real e-mail addresses, but to everyone else it will look like they e-mail each other @yourdomain.tld, yet they get responses back to their own e-mail account.

My thanks olso to stickman and chort. I am gradually figuring out what to do.