eWall History

We started with a very simple product: MailFilter — a plug-in for the mail server ArGoSoft Mail Server. MailFilter had a very limited set of pre-defined conditions and actions, and a typical filter looked like this:

if Subject contains 'viagra'
then delete message

Very soon after, MailFilter had been wrapped into a proxy framework and eWall v1.0 was born in March 2003. It had the same features as MailFilter, but was now able to work in conjunction with any mail server.

As customers have asked for new actions and conditions, we have been adding them, making eWall's conditions and actions list longer, but we still didn't have the level of flexibility we desired. Then, in addition to the pre-defined list of conditions and actions, the Javascript engine was been added into eWall v3.0, becoming the first SMTP proxy with an internal scripting engine and open API. Of course, the main purpose of eWall is to protect mail server from spam and viruses, but using the Javascript engine and open API allowed you to write custom filters for virtually anything. As an example, you could write a script to open a garage door if the message contained the text 'OPEN GARAGE DOOR', or turn on the coffee machine through x10 interface.

Another unique feature of eWall is EWLSP, a Transparency module, that allows the mail server see the actual originating IP address behind eWall, and allows all IP-based features of the mail server to be used. Please click here to read more about the Transparency module.

We continued experimenting with Javascript, but after time, concluded that as powerful as javascript was, it was not suitable in a server side environment. The Javascript is primarily designed to work in web browsers, on the client side. It is a simple, clean and flexible language, but it doesn't have the sufficient code base and libraries to be suitable for the server environment. For example, making a database connection, or sending DNS requests will require installing different third-party components, rare for such server-side things. Of course, this can be done with new eWall API objects, but it still goes against the the generally accepted Javascript purpose — the interacting with client-side web browser API.

We started to look at other server-side scripting languages and found very quickly that PHP is suitable for eWall needs: this is time-proven, fast, and lightweight scripting engine, which has plenty of free libraries for almost anything. From DB drivers for major RDBMS engines, such as Oracle, PostgreSQL or MySQL, to lightweight socket libraries — everything can be plugged-in to the PHP engine, and the vast majority of this software is free.

The PHP engine has now been incorporated into eWall v4.0, along with a repository of ready-to-use filters, that are themselves, snippets of PHP code. Although PHP is widely recognized as a programming language for web site development, and the idea to use it for mail filtering may look strange, we recommend you try eWall to see how well it filters SPAM and how flexible and scalable it is. Try it FREE today!