(PRWEB) November 3, 2004
The XWall greylisting filter is simply by nature. If an email is rejected by a mail server, the sender automatically sends it again; itÂs part of the SMTP protocol. XWall greylisting blocks the message the first time, making the mail sender send the message twice; nothing more, nothing less. Spammers have a real problem with that, because they donÂt wait to see if a message gets through. Any compliant mail server will have no problem passing the greylisting filter, but spam rarely does.
Interested in the detail? As many know, SMTP mail was considered unreliable, even before the age of spam. The SMTP standard requires the sending server to resend any messages not successfully delivered. A mail server will attempt redelivery of bounced message after 5 - 10 minutes. The spammers however use email differently. Throughput per hour is what counts so why waste time retrying a connection? Someone had a great idea. Why not deny delivery at the first attempt? Then when the message arrives a second time, allow it to pass. It is a truly innovative idea with great results and very few false positives. XWall 3.31 features this greylisting filter. XWall keeps record of each unique message by sender, recipient and server, called a triplet. Messages not seen before will be rejected, sending a temporary message handling error. When the triplet shows up a second time it will be accepted. Exclusions can be set for some none standard mail delivery agents sometimes used by newsletters. The ESATInformer report allows the user to spot these situations easily
XWall and ESATInformer are valuable tools in the fight against spam. Consultants and Installers like the server based approach, the low cost and unlimited user count. It allows them to present a complete spam solution to their customers at an affordable price. Xwall and ESAT are widely used in large corporations, schools and universities. The spam control system can be directly purchased from Ceratec Inc. as software or as a preinstalled hardware solution. Ceratec Inc. also provides technical support by phone, email and forum.
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