标题: MailEssentials reverse DNS doesn't work [打印本页] 作者: deckking 时间: 2008-4-5 03:06 标题: MailEssentials reverse DNS doesn't work MailEssentials Reverse DNS doesn't work (MailEssentials中如何把DNS解析失败的邮件标为垃圾邮件?)
Two questions here about MailEssentials v12:
1. I already enabled Reverse DNS check by: MailEssentials configuration -> Anti-SPAM -> Header Checking -> General Contd. -> 'Verify if sender domain is valid'. But I still get emails from some weird domains and they're not detected, and also I can send a mail from other servers that claims to be Bill.Gates@microsoft.com. How shall I set it to delete/mark those emails that failed with reserver DNS check?
2. MailEssentials ignores NDR e-mails, this cause a big problem when spam mail coming in as NDR. How to stop Spam of such kind?
My ME filters sequence is the default.
Thanks作者: gfisoftware 时间: 2008-6-11 15:58 标题: RE: MailEssentials reverse DNS doesn't work Reverse DNS does not check whether a specific email was delivered from a particular domain, only whether that domain actually exists. As a result, it is not particularly effective in filtering out spam. Effective methods to determine whether the sending ip of an email matches that domain require methods like SPF (sender policy framework - www.openspf.org). This does require additional configuration on the sending server though, which limits its use amoung smaller networks. SPF is a configurable module in Mailessentials.
NDR spam (Backscatter spam) has recently surged in use the last two months. Older versions of Mailessentials did not have specific filters for this spam. The latest build of mailessentials does include a filter specifically to target this NDR software. There is a knowledgebase article which goes into more detail for this http://kbase.gfi.com/showarticle.asp?id=KBID003322