Eric Wilde
BSM Development
44 Whitewood Circle
Norwood, MA 02062
Phone: 781-551-0153

Mail Filtering Software For Production Environments and ISPs

Norwood, MA -- January 20, 2003 -- BSM Development ( announces that the latest release of MailCorral, a mail filtration program, for use on Unix and Linux systems and available for download from the company's Web site, contains many features that will be of great interest to users wishing to do mail filtering in production environments, especially ISPs.

MailCorral filters mail delivered to Unix and Linux systems via the standard Simple Mail Transfer Protocol (SMTP) interface, through sendmail, the Mail Transfer Agent (MTA) commonly used in production systems and by ISPs. It watches all mail traffic entering the system and inspects it for the presence of harmful viruses and annoying spam. It detects and renders harmless the viruses as well as identifying and sidelining the spam.

Viruses are effectively removed through a two step process that concentrates on preventing them from being automatically launched on a recipient's workstation. Since the algorithms employed do not depend on virus signatures, they are much more resilient and work against new as well as known viruses, thereby eliminating the need for constant updating of signature databases. Email messages bearing viral payloads are laundered to disable the virus' self-launching capabilities and then passed on to the recipient.

A copy of the unaltered, original message is placed in a holding area (called the corral), where it is retained for a short time. The recipient of the altered message may easily release it for delivery to themselves, unchanged, by sending a message to a mail handling robot. No intervention by anyone other than the recipient is required to release the message, thus making this unattended, automatic feature especially desirable to any facility that is handling large volumes of mail.

Spam is identified through the use of plug-in spam identifiers which make the decision about whether a message is actually spam or not. The message headers and key portions of the message are passed to the identifier while large attachments that are irrelevant are not, thereby speeding up the process of spam identification. MailCorral decodes all encoded plain text and HTML MIME components to find viruses and spam hidden by encoding. It only passes decoded messages to the spam identifier so that it can concentrate on identifying spam and not have to worry about unraveling the many convolutions of MIME documents. The spam identifier can be upgraded at any time without effecting the actual processing of email, which is always done by MailCorral.

Spam can be marked as such and delivered, it can simply be discarded or it can be sidelined in the corral (the most popular choice) where it can be delivered to the recipient at a later date. The related product by BSM Development, SpamCorral, allows the recipients of sidelined spam to quickly and easily decide whether they actually wish to see the spam or otherwise allow the system to dispose of it. The requirements on the recipient's time, to deal with spam, are kept to a bare minimum, as little as a few seconds a day and no intervention by facility staff is ever required.

SpamCorral sends a notification to each recipient, once a day (more frequently if you choose), showing them all of the spam that they would have received and listing its details. The recipient has the option of replying to the notification, to request that specific pieces of spam be remailed to them or ignoring it altogether. The annoyance of dealing with spam is kept to a very short time and only happens once a day.

If the recipient ignores the notification, the spam is silently deleted by SpamCorral. Total time required of the recipient: a few seconds to peruse the notification and decide to ignore it. Total involvement by system personnel: none.

If the recipient replies to the notification (replies to the notification are processed automatically by a robot), they can select which pieces of spam they wish to receive. You never know. Someone might send you a valuable piece of spam one day. In this case, the recipient spends ten or fifteen seconds replying to the notification and SpamCorral sends them their request. Once again, the unrequested spam is deleted silently and the system personnel are not involved in any way.

A big advantage of filtering mail, on the Unix/Linux system delivering it, is that MailCorral can stop viruses and spam before they ever get to the recipients. This can reduce network traffic (for spam) and guarantee that a virus will not get launched by mistake. A second advantage is that, since all mail passes through sendmail on the Unix/Linux system, it is an easy, centralized place to insert the filter and one that system personnel will be very comfortable with. No changes to any workstations or mail readers, with the attendant maintenance headaches, are required.

Other features that are sure to be of use are the ability to let individual users select their own filtering options through a Web page (a simple, easy to customize template is provided that let's you provide a Web page with your own look and feel) and support for virtual users. Virtual users can set their filtering preferences too, with their settings being stored in a global database instead of the user's home directory. All users have full control over how their email is filtered with no setup or maintenance burden placed on the system staff.

For more information about these products, see the company's products Web page,, email or phone 781-551-0153.