Email security best practices for using SPF, DKIM, and DMARC

Key points

After you read this article, you will have a better understanding of the following topics:

  • Best practices for email security for your business

  • The main email authentication methods

  • Why should you use email security best practices

  • Benefits of using SPF, DKIM, and DMARC email authentication

  • Maintaining your email account with trusted email security protocols

  • Sender Policy Framework (SPF)

  • DomainKeys Identified Mail (DKIM)

  • Domain-based Message Authentication, Reporting & Conformance (DMARC)

Incorporating best practices for email security for your business

The main goal of using the best email security measures is email authentication, which ensures that your recipients know you're sending them messages. With good email authentication methods, at least one of these protocols will authenticate your mails. However, without them, it's unlikely that your message will reach anyone.

What are the main email authentication methods?

SPF, DKIM, and DMARC are the three most often used email protocols. Together, these regulations serve as a safety net for both you and your email recipients. Without them, fraudsters can easily send bogus messages purporting to be you. To avoid compromising themselves or their recipients, email senders employ the email authentication mechanisms mentioned in the following sections.

Sender Policy Framework (SPF)

Sender Policy Framework (SPF) is a digital instrument that determines which IP addresses are safe to use to deliver messages. Your domain's email has a list of validated IP addresses that can send emails for you. When SPF is properly configured, your messages are checked against a list of sending sources in the SPF record.

DomainKeys Identified Mail (DKIM)

DomainKeys Identified Mail (DKIM) is a mechanism that uses encryption to sign your email message and ensure that it was not altered during transit. Email recipients can verify that your message is from you by using the public keys provided in your DKIM records.

Domain-based Message Authentication, Reporting & Conformance (DMARC)

Domain-based Message Authentication, Reporting, and Conformance (DMARC) is a protocol that employs three standard policies to manage communications and determine how to treat them. DMARC also works in tandem with DKIM and SPF, providing an additional layer of protection. DMARC authenticates the domain from which each message originates and can deliver XML reports to the server of your choice. These reports give information that helps server administrators decide how to implement email regulations.

Why should you use email security best practices?

You may feel that distinguishing between a phony and an authentic email is simple, but fraudsters are becoming increasingly sophisticated. They can utilize technology to bypass your defenses. Every day, more than 30,000 websites worldwide are hacked. Spammers seek access to your domain for a variety of reasons:

To use your good IP reputation to carry out successful phishing attacks on unsuspecting recipients

  • To get sensitive data of your user base in order to commit fraud or cause more harm

  • To gain control of your domain through a password reset email

The reasons could go on and on about why hackers want your personal information. If you do decide to start utilizing the best email security practices, what are the benefits? Let's review them in the following section.

The benefits of using SPF, DKIM, and DMARC email authentication

If you provide email services to your consumers, do you believe you'd still have them if your domain appeared spammy? Your customers are likely to depart your business for one with higher standards. Using SPF, DKIM, and DMARC helps you keep a positive reputation while also providing various other benefits.

Gain customer trust

As a business, you should never underestimate the value of your customers' trust. When people conduct business with you, they want to know that you are trustworthy and take appropriate measures.

If you run an ecommerce company and send your email list several messages, customers must be able to trust that your messages are secure and will not expose them to fraud. Maintain high standards and do anything you can to keep their faith. If you lose it, you will never get out of the junk folder.

Protect your brand from cyberattacks

Hackers target both small and large corporate enterprises, so nobody is safe. That is why you require excellent email security to safeguard your domain from cybercriminals. This concept falls under the same category as trust.

You don't want someone impersonating you and executing scams to harm your brand. Using these protocols ensures that your messages reach their intended receivers and protects your connections from internet scammers.

Establish a rapport with your leads

Every internet business requires new leads. It is tough to grow or even maintain your business functioning properly without new leads. In email marketing, there are numerous factors that might prevent your communications from reaching potential clients; do not let incorrect email protocols be one of them.

How to maintain your email account with email security protocols

You can examine your server's records when sending marketing emails or interacting with business partners about significant issues. Once you've identified each protocol, you can modify the parameters to follow best practices. Start with SPF.

Best practices for SPF

Remember, the SPF protocol verifies the sender IP address and compares it to a list of allowed sources. Proper SPF protocol prevents domain spoofing, but here's how to use it effectively.

Don't crowd the SPF record

If you add too many sending sources to your SPF record, there may be problems. Having too many sending sources may lead servers to reject your messages. If your communications are repeatedly flagged, this might harm your reputation and reduce deliverability rates.

Forget the +all component of your SPF record

While the +all option is undeniably convenient, it can have an impact on SPF. Instead of confirming the required IP addresses for security reasons, the option selects all domains, including those that are fraudulent. Malicious actors can exploit your server by allowing any domain to submit messages.

If you are not practical with your SPF protocol, your domain may be blacklisted completely, which means your customers will no longer receive your communications. Regaining such trust is nearly impossible.

Best practices for DKIM

While you might enable the DKIM protocol's default settings, this is not recommended. You know how when you create a password for an account, the system evaluates it from weak to strong? You might use a weak password, but creating a strong one is also simple. Here's how to use DKIM to protect your domain.

Make DKIM keys longer

When validating your message, the recipient's server checks your credentials against a public key from the DKIM record. As a rule of thumb, DKIM keys should be at least 1,024 bits long. Use this as a standard, or your DKIM keys will be rejected, rendering DKIM completely useless. It may be advisable to increase the length to 2,048 bits.

Change your keys regularly

Sure, your DKIM keys could be strong right now, but there's no telling how many hackers have attempted to break the cryptographic algorithm. In any case, if a hacker is persistent enough, they will eventually uncover your DKIM key and exploit your domain. To avoid this, rotate your DKIM keys on a regular basis.

If you save critical information, you should rotate your keys more frequently. The same goes for key length. The more sensitive the material, the longer the key should be. Also, give each consumer a unique key; do not use the same one.

Best practices for DMARC

What's the use of having an extra layer of protection if it has holes? If you haven't deployed DMARC yet or are using the default policy, you should review your DMARC record and strengthen your protection.

Don't dismiss parked domains

Many people see parked domains as dormant and insignificant, however a hacker can easily impersonate these names. Don't become complacent. Configure DMARC policies for your parked domains as well.

Try a gradual approach

Starting your DMARC protocol with a reject policy may be a mistake. It's advisable to begin with the p=none policy so that you can watch your DMARC reports as they arrive and learn more about your status. After passing the monitoring phase, enable p=quarantine, followed by p=reject.

Even after you've achieved DMARC compliance, don't give up. Hackers never give up; they merely find new ways to breach your defenses. The best course of action is to continue monitoring your domain for configuration issues or other indicators of a problem.


Using best practices for appropriate email authentication will safeguard your domain and its recipients from spoofing, phishing, and other damaging schemes that could harm your reputation. Only a few best practices were mentioned. Maintaining these procedures will ensure that your domain is trustworthy for your clients.

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