AntiSPAM

Sophos UTM and DKIM

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DKIM, also known as DomainKeys, is a procedure for determining the authenticity of emails. The basic functionality is explained quite simply: The sending mail server calculates a hash value for each mail it sends and appends this hash to each mail in the e-mail header. The receiving mail server can evaluate the signature and also determine the ... Read more

Open Source AntiSPAM Appliance: Proxmox Mail Gateway

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The Austrian company Proxmox has published the spam filter "Mail Gateway" as open source under the GNU AGPL v3 license. This means that the spam filter can be used free of charge. I've been looking for a SPAM filter for test environments for a while now, so I'm taking a closer look at the Proxmox solution. Here is an overview of the ... Read more

Exchange Server: Prevent mail spoofing

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Mail spoofing is often used to persuade users to open dangerous attachments in emails. The aim is to make it look as if the email is coming from a colleague or a device such as a scanner or Fax2Mail. Mail spoofing is used to falsify the sender's address so that it looks to the user as if the email is coming from an internal ... Read more

Exchange: Delete mails from mailboxes

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Bad mails happen in the best of families. Sometimes it is a virus, or an email that should not have been sent. Exchange Server offers the possibility to delete mails from mailboxes. Especially with SPAM or virus waves, it can be very useful to know how to do this. This article applies to Exchange 2010, 2013 ... Read more

Sender Policy Framework (SPF): How it works and when you shouldn't use it

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How SPF works SPF (Sender Policy Framework) is a simple method for identifying forged senders and blocking them as SPAM. The way it works is simple: The domain owner (e.g. me with the domain frankysweb.de) publishes a TXT record (SPF record) in the DNS which contains the mail servers from which I send mails. For example, if my mail server ... Read more