--- title: "How SPF, DKIM, and DMARC quietly protect every email you send? | DuoCircle" description: "How SPF, DKIM, and DMARC quietly protect every email you send?" image: "https://www.duocircle.com/images/og-default.png" canonical: "https://www.duocircle.com/blog/email-security/how-spf-dkim-dmarc-protect-every-email-you-send-securely/" --- Quick Answer SPF, DKIM, and DMARC each handle a distinct part of email authentication. SPF verifies that the sending IP is in the domain's authorized list. If not, the message is treated per the SPF qualifier: SoftFail (\~all) routes to spam, HardFail (-all) blocks delivery. DKIM adds a cryptographic signature over the message headers and body using a private key; the receiver verifies it with the public key in DNS. Unlike SPF, DKIM survives forwarding because it does not depend on the sending IP. DMARC ties SPF and DKIM to the visible From-header domain, requires alignment, and instructs receivers on failures: p=none lets failures through with reporting only, p=quarantine routes them to spam, p=reject blocks them entirely. SPF needs ongoing maintenance as sending sources change; DKIM keys should be rotated; DMARC should advance from none to reject in stages. How SPF, DKIM, and DMARC quietly protect every email you send? Your browser does not support the audio element. [ Download episode](https://media.mailhop.org/duocircle/images/2025/06/How-SPF-DKIM-and-DMARC-quietly-protect-every-email-you-send.mp3) Share [ ](https://www.linkedin.com/sharing/share-offsite/?url=undefined%2Fblog%2Femail-security%2Fhow-spf-dkim-dmarc-protect-every-email-you-send-securely%2F "Share on LinkedIn") [ ](https://twitter.com/intent/tweet?text=How%20SPF%2C%20DKIM%2C%20and%20DMARC%20quietly%20protect%20every%20email%20you%20send%3F&url=undefined%2Fblog%2Femail-security%2Fhow-spf-dkim-dmarc-protect-every-email-you-send-securely%2F "Share on X/Twitter") [ ](https://www.facebook.com/sharer/sharer.php?u=undefined%2Fblog%2Femail-security%2Fhow-spf-dkim-dmarc-protect-every-email-you-send-securely%2F "Share on Facebook") [ ](https://reddit.com/submit?url=undefined%2Fblog%2Femail-security%2Fhow-spf-dkim-dmarc-protect-every-email-you-send-securely%2F&title=How%20SPF%2C%20DKIM%2C%20and%20DMARC%20quietly%20protect%20every%20email%20you%20send%3F "Share on Reddit") [ ](mailto:?subject=How%20SPF%2C%20DKIM%2C%20and%20DMARC%20quietly%20protect%20every%20email%20you%20send%3F&body=Check out this article: undefined%2Fblog%2Femail-security%2Fhow-spf-dkim-dmarc-protect-every-email-you-send-securely%2F "Share via Email") ![protect every email](https://media.mailhop.org/duocircle/images/2025/06/Office-365-migration-8976.jpg) Every email sent from your domain needs to be from a clean, legitimate sender. Even a **single communication attempt** by a threat actor impersonating your brand can lead to phishing, spoofing, [business email compromise (BEC)](https://www.infosecurity-magazine.com/news/manufacturing-loses-60m-bec/), and ransomware attacks. This is exactly where SPF, [DKIM](/resources/what-is-dkim), and DMARC step in every time an email is sent from your domain. Together, these protocols make quiet security checks in the background, fulfilling their responsibility like invisible guards. They **verify your identity**, safeguard the content, and ensure your emails aren’t spoofed, altered, or used for [phishing attacks](https://www.cybersecuritydive.com/news/phishing-attack-us-government-constant-contact/601134/). ## SPF verifies the sender’s IP SPF works by verifying each time if the **email sender’s IP address** or [mail server](https://www.techtarget.com/whatis/definition/mail-server-mail-transfer-transport-agent-MTA-mail-router-Internet-mailer) is listed in the SPF record. If yes, the email passes the SPF check and lands in the recipient’s inbox. If not, it is either treated as per Soft Fail (the email gets placed in the recipient’s [spam folder](https://cybernews.com/news/microsofts-breach-notification-emails-end-up-in-spam-folder/)) or Hard Fail (the email is denied entry). [![spam folder](https://media.mailhop.org/duocircle/images/2025/06/spf-record-generator-9023.jpg)](https://media.mailhop.org/duocircle/images/2025/06/spf-record-generator-9023.jpg) _However, SPF is a very sensitive protocol; it gets erroneous with even a slight misconfiguration_. Therefore, the person in charge of your [SPF record](/content/spf-records) must regularly update the sending sources mentioned in it. They should remove old or unused services that no longer send emails on your behalf, while also ensuring to add sending sources belonging to **new joiners and vendors**. ## DKIM seals the email with a signature DKIM is like a digital wax for your outgoing emails. It works by adding a cryptographic signature that’s unique to your domain and the email’s content. When the **recipient’s server receives** the email, it verifies the signature using your domain’s [public key](https://www.techtarget.com/searchsecurity/definition/public-key) published in DNS. If the content has been **altered in transit**, the signature won’t match, helping detect tampering. Unlike [SPF](https://autospf.com/blog/spf-guide-understanding-sender-policy-framework/), DKIM remains valid even when emails are forwarded, making it a reliable way to prove the message came from you and hasn’t been changed along the way. [![domain’s public key](https://media.mailhop.org/duocircle/images/2025/06/dmarc-report-6785.jpg)](https://media.mailhop.org/duocircle/images/2025/06/dmarc-report-6785.jpg) ## DMARC is the final gatekeeper DMARC brings SPF and DKIM together and adds an important [email security](/) layer to your **outgoing emails**. It checks whether the domain authenticated by SPF or DKIM matches the domain visible to the recipient (the “From” address). This helps prevent attackers from using your domain, even if they bypass SPF or DKIM checks by using lookalike servers. Well, DMARC works beyond alignment; it helps the **domain owner instruct** the receiving servers on how to handle unauthorized emails sent on their behalf. There are three [DMARC policies](/dmarc/a-guide-to-advancing-dmarc-policies-for-enhanced-email-deliverability/) that domain owners can choose from. [![quarantine’ policy sends illegitimate emails](https://media.mailhop.org/duocircle/images/2025/06/dkim-selector-0903.jpg)](https://media.mailhop.org/duocircle/images/2025/06/dkim-selector-0903.jpg) - _The ‘none’ policy lets suspicious emails pass through and land in the inbox as usual_. - The ‘**quarantine’ policy sends** [illegitimate emails](https://www.linkedin.com/pulse/illegitimate-emails-protect-yourself-indigo-it-limited) to spam folders so that recipients proceed with them cautiously. - The ‘reject’ policy blocks them entirely, preventing any chances of email abuse. ## **Conclusion** Every time you hit the ‘send’ button, SPF, DKIM, and [DMARC](/resources/what-is-dmarc) work silently to evaluate if the email is potentially fraudulent. With so many email-driven cybercrimes happening these days, it’s **important for companies** of all sizes to ensure these protocols are set up properly. ## Topics DKIMDMARCemail securityspfSPF record ![Brad Slavin](https://media.mailhop.org/dmarcreport/images/team/brad-slavin.jpg) Brad Slavin General Manager General Manager at DuoCircle. Product strategy and commercial lead across the email security portfolio. ## Secure your email infrastructure Protect, authenticate, and deliver. Contact our team to find the right solution. [Contact Sales](/contact/) [Explore Products](/products/) ## Related Articles [ Email Security 6m Building a zero-trust security model for emails Dec 11, 2024 ](/blog/email-security/building-a-zero-trust-security-model-for-emails/)[ Email Security 7m How email authentication helps you prove sender identity under ISO 27001 Nov 18, 2025 ](/blog/email-security/how-email-authentication-helps-verify-sender-identity-for-iso-27001/)[ Email Security 6m How do you achieve SPF alignment to enhance email security and deliverability? Mar 25, 2025 ](/blog/email-security/how-spf-alignment-improves-email-security-and-deliverability/)[ Email Security 3m How to add a DKIM signature for your domain in Zoho? 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