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From SPF to DKIM to DMARC: Building a Robust Email Security Strategy

Emails are a vital part of the modern world. Worldwide, people send over 347.3 billion emails daily, and the amount of information transferred via email is simply unfathomable. It’s crucial to consider your organisation’s email security when you realise how many emails go out of your organisation every day.

In this blog, we will demystify the concepts of SPF, DKIM, and DMARC, and show you how to fortify your organisation’s email security with just a few straightforward steps.

Understanding SPF

Sender Policy Framework (SPF) is like a digital passport for your emails. It’s the technology that verifies the identity of the sender.  

Think of an SPF record as a digital bouncer for your email server. Internet Service Providers (ISPs) can use the technology to authenticate whether a mail server is authorised to send emails from a specific domain. This nifty tool puts a stop to email spoofing by ensuring that the sender of an email is the real deal. It’s also the reason why your outgoing emails don’t end up in the dreaded spam folder—the SPF record vouches for the email’s legitimacy.

An SPF record is a DNS TXT that lists all the servers allowed to send emails from a domain. The SPF framework checks the SPF record to flag and reject any server that attempts to spoof a domain without authorisation.

SPF essentially works as a record to ensure that authorised domains are sending emails and that you don’t receive spoofed emails that could have nasty consequences for your organisation. SPF also checks the SENT (what you see in Outlook) and FROM (the real email address sending the email) fields to ensure they match; this is a common attack method used in Phishing. It acts as the first line of defence and redirects any rejected emails to the spam bin.

Demystifying DKIM

DomainKeys Identified Mail (DKIM) is an authentication service that uses digital signatures to verify the legitimate source of an email and ensure that the sent and received emails are the same, thus preventing tampering during transit.

However, it does not prevent spoofing or phishing, as it only confirms that the signature has not changed from being sent to being received. Nonetheless, DKIM confirms that your organisation’s emails have not been hijacked or altered during transit. The recipient’s system finds the sender’s public key at a server level to ensure that it matches the key in the email, making DKIM signatures invisible.

Mastering DMARC

Domain-based Message Authentication, Reporting & Conformance (DMARC) is an email authentication, policy, and reporting protocol. Using SPF and DKIM as a foundation, DMARC complements the former two standards by helping update them to the needs of the modern world. 

Specifically, DMARC is designed to satisfy the following —

By adding policies to enhance security further and increase your organisation’s protection, DMARC can complement SPF and DKIM fully, ensuring that your organisation’s email security is at the highest level.

What’s the Difference?

Let’s compare the differences between SPF, DKIM, and DMARC in a straightforward comparison table.

MethodPurposeHow It WorksStrengthsWeaknesses
SPF (Sender Policy Framework)Verifies sender’s IP address.SPF checks the sender’s domain’s SPF record to see if the IP address matches authorised servers. Authorised servers are listed in the SPF record.Ease of Implementation: It is simple to set up by adding a TXT record in DNS settings.  

Straightforward Authentication: Directly verifies the sender’s IP address.  

Reduces Spoofing: Prevents unauthorised parties from impersonating legitimate senders.  
Dependence on IP Addresses: This may be problematic when using third-party services.  

No Message Integrity Verification: This doesn’t verify email content integrity.
DKIM (DomainKeys Identified Mail)Verifies email message authenticity.DKIM adds a digital signature to the email header.   The recipient’s server checks this signature against the public key in the DNS.  Message Integrity: Ensures email content hasn’t been altered.  

Authentication: Provides strong authentication.
Complex Setup: Involves cryptographic keys and DNS records.

Key Management: Requires proper key management.
DMARC (Domain-based Message Authentication, Reporting, and Conformance)Enhances email authentication.DMARC builds on SPF and DKIM results.   It instructs email servers on how to handle unauthenticated emails.Comprehensive Protection: Combines SPF and DKIM for robust authentication.  

Policy Enforcement: Allows domain owners to specify actions for unauthenticated emails.
Setup Complexity: Requires proper configuration of SPF and DKIM.  

Implementation Effort: All three methods are needed for optimal results.

Remember, while each method has strengths and weaknesses, implementing all three together ensures better email authentication and deliverability.

Building a Robust Email Security Strategy

SPF, DKIM, and DMARC ensure your organisation’s safe and secure emails. Implementing all three tools into your organisation can easily safeguard your collective inbox from phishing or fraudulent spoofing attacks.

The first significant step in ensuring your organisation has a robust email security strategy is finding a solution that encapsulates all three protocols. Empower your email solution by implementing a powerful tool that ensures your organisation’s email security. Live worry-free, knowing that your email is well-protected.

Another essential part of email security is creating a security-conscious culture within your organisation. While staying protected on the server level is vital, ensuring your organisation is protected against bad-faith actors is also crucial.

Important, everyday things like using secure networks, 2FA, good password hygiene, and anything else to ensure that your email accounts are secure are just as vital as the technical side of security, so neglecting them could be as catastrophic as failing to implement any of the three protocols above.

Why Not Just Add a DMARC Record? 

Many companies configure their website, payroll system, and other cloud-based SaaS tools, including HR and marketing solutions, to send emails using their own domain name. How do you know these are all covered fully by SPF and DKIM? Enabling DMARC without including every valid source may reject some crucial messages.

Your domain’s SPF records authorise which mail servers are allowed to send emails on its behalf. DKIM adds a digital signature to outgoing emails, ensuring their integrity, and DMARC instructs the recipient’s server on handling emails that fail SPF or DKIM checks.

So you can see they all make for a better secure solution.

Email security is a vital part of the modern world. With emails being crucial to any organisation, ensuring high email security is critical. This is why SPF, DKIM, and DMARC exist, as a standard to ensure everyone has access to the best email security available.

Get in touch with us today to find out more on how to implement DMARC into your email security strategy. If you don’t know where to start our experts can support and guide you through setting up email security within your organisation.

Get in touch with us now and see how we can help.