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Jesper Knudsen, Founder, ScanMailX.com
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SpamAssassin is beyond any doubt the best open source email spam filter and when in 2006 we decided to add a spam filter to the mail module of Zentyal Linux small business server, SpamAssassin was clear choice for us. The mail filtering capabilities are integrated within the Zentyal mail server module, but can also be used to filter incoming and outgoing mail for an existing mail server.
Heidi Vilppola, Zentyal Development Team, Zentyal
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We use SpamAssassin for several clients here in Qatar , As a company providing several types of anti-spam solutions we can easily certify that SpamAssassin has the least number of false positives compared to its commercial counterparts like Barracuda and Sonicwall . SpamAssassin is the only solution you can use if you want to relay emails ( smarthost ) to an smtps server ( ofcourse with stunnel and postfix ) , most of commercial appliances doesnt support this feature .
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