Both DKIM and DMARC are integrated into AppRiver's Email Threat Protection filter policy as sender verification tests.

What is DKIM?

DKIM (Domain Keys Identified Mail) is an email authentication technique that allows the recipient to check that an email was indeed sent and authorized by the owner of that domain. This is done by giving the email a digital signature.

Why is DKIM important?

Differently from SPF, which enables AppRiver to send emails on your behalf, DKIM records add a domain name identifier to your message, using cryptography techniques to validate it as the recipient gets the email. That way, the ISPs receiving the incoming emails from such domain may use this digital signature to help them determine if each email is legitimate. 

What is DMARC?

A DMARC (Domain Message Authentication Reporting & Conformance) policy allows a sender to indicate that their messages are protected by SPF and/or DKIM, and tells a recipient what to do if neither of those authentication methods passes – such as junk or reject the message. DMARC removes guesswork from the recipient’s handling of these failed messages, limiting or eliminating the user’s exposure to potentially fraudulent & harmful messages. DMARC also provides a way for the email recipient to report back to the sender about messages that pass and/or fail DMARC evaluation.

Why is DMARC important?

With the rise of the social internet and e-commerce, spammers and phishers have a tremendous financial incentive to compromise user accounts, enabling theft of passwords, bank accounts, credit cards, and more. Email is easy to spoof and criminals have found spoofing to be a proven way to exploit user trust of well-known brands. Simply inserting the logo of a well-known brand into an email gives it instant legitimacy with many users.

Users can’t tell a real message from a fake one, and large mailbox providers have to make very difficult (and frequently incorrect) choices about which messages to deliver and which ones might harm users. Senders remain largely unaware of problems with their authentication practices because there’s no scalable way for them to indicate they want feedback and where it should be sent. Those attempting new SPF and DKIM deployment proceed very slowly and cautiously because the lack of feedback also means they have no good way to monitor progress and debug problems.

DMARC addresses these issues, helping email senders and recipients work together to better secure emails, protecting users and brands from painfully costly abuse.

How do DKIM and DMARC combat phishing? 

DKIM helps to validate the actual email content and headers, but it doesn’t prevent attackers from abusing the header-from address. It also doesn’t tell what a receiving server should do if a signature validation fails. This is where DMARC comes into the picture. 

DMARC is a way to make it easier for email senders and receivers to determine whether or not a given message is legitimately from the sender, and what to do if it isn’t. This makes it easier to identify spam and phishing messages, and keep them out of peoples’ inboxes. 


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