Best authentication practices for email senders

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You may not think much about it, but your emails go through many gateways to make it to your contact. The same goes for anyone sending messages to you. The process is called Email Authentication, and it’s crucial for all email domains. You and your business do many things to protect your privacy, but cyber threats can come from anywhere, even in your inbox. Knowing how to optimally authenticate email in your various systems is essential.

Each message or possible junk email could be a potential phishing attack waiting to happen. The best authentication practices for email are related to your overall email security. Your IT department employs strategies to protect you from unauthorized individuals accessing sensitive data, and they are your best line of defense to maintain privacy. Learn the best authentication practices for email senders and how you can incorporate them into your domain.

What is email authentication, and why is it important?

As long as emails reach their destination nine times out of ten, email senders are not concerned with much else. Everyone is guilty of it, but sometimes, when something works, the details are not considered. In order to authenticate email, your business should think about the details.

Email authentication uses several standard methods to help your server manage or reject unauthorized messages. These techniques are commonly used with most email systems, verifying that each message is legitimate and wasn’t intercepted by cybercriminals. Email messages are sent by Simple Mail Transfer Protocol (SMTP).

The typical authentication techniques are:

  • Sender Policy Framework (SPF)
  • DomainKeys Identified Mail (DKIM)
  • Domain-based Message Authentication, Reporting & Conformance (DMARC)
  • SMTP Authentication (SMTP AUTH)

SMTP is the standard form of email sending — and it does not include authentication. Without authentication, your email might not be delivered, or they might be targeted for cyberattacks. You can avoid delivery issues by using the above authentication methods to authenticate email.

Yet, other than better email deliverability, why else should you use common email authentication techniques?

What are some benefits of email authentication?

Anyone can be a target for criminals, meaning if you’re using a public domain, you should use email authentication best practices. By using SPF, DKIM, DMARC, SMTP AUTH, and other best practices, your business will enjoy the benefits.

Better brand image

If you’re selling products and services to repeat customers, chances are that you have a reputation with them. A good reputation is crucial in business and often leads to more repeat customers and higher sales figures. It also tells potential customers you’re reliable and can take care of their needs.

More trust and industry credibility

Often, online businesses need to reach out to their customers in a variety of ways. This communication includes emails, newsletters, social media, blog posts, and more. When your email is properly authenticated, it leads to a greater sense of trust in your offerings and better engagement.

Strong security

With more robust authentication protocols in place, your domain is more prepared for hackers who would try to impersonate your brand. Through structured verification policies, incoming and outgoing messages will be scanned and routed to the appropriate channels.

Whether you’re using email platforms like Gmail, Outlook, or Amazon WorkMail, enabling more robust authentication practices will keep you and your clients safe. Learn more about the authentication standards and how to authenticate email for email senders.

An overview of common email authentication techniques

Unfortunately, emails aren’t a secure communication method, but with verified techniques, such as SPF, DKIM, DMARC, and SMTP AUTH that can change. Authentication requires that server owners use all three techniques to maximize their protection. Here’s some brief detail on each method.

What is Sender Policy Framework (SPF)?

Each message you send and receive comes from somewhere, and since you don’t know where they come from, SPF is a useful protocol to authenticate email. SPF verifies the sending source for each message flowing through your domain. Each source is compared to a list to confirm that it’s authorized to send messages on your behalf.

You can adjust the SPF record through altering the TXT record located in your Domain Name System (DNS). If a receiver sends a message, but the source isn’t verified, then the message is rejected.

How DomainKeys Identified Mail (DKIM) helps with email authentication

We’ve discussed how senders are authenticated, but how are the messages themselves cleared for delivery? Using the DomainKeys Identified Mail (DKIM) method, your domain identifies a digital signature or an encrypted key, that can confirm the authenticity of a received message. More importantly, this process works with both public and private DKIM keys.

DomainKeys Identified Mail (DKIM) methods do their job by enforcing the expectation that both keys match. The data concerning the DKIM keys are in the DKIM record, which is also attached to your DNS. If the DKIM keys don’t match, then the message is rejected. By altering these keys often, you can better protect your sensitive information.

Address the limitations of DMARC

The third way to authenticate email works in tandem with SPF and DKIM to add a stronger layer of security for your server. While DMARC has its own role, it also uses SPF and DKIM to authenticate email. If you are sing a DMARC record that consists of a TXT record, you need to add it to your DNS to enable it.

In addition to confirming that the return address and signing addresses match the DNS records, DMARC governs how your server handles questionable emails. Using this protocol, you can set a policy using p=none, p=quarantine, and p=reject. Together, these methods create an impenetrable layer of email security that makes your company a safer option for regular activities.

Still, while SPF, DKIM, and DMARC are relevant to email security and authenticating email, there’s still more you can do to protect email senders.

What are some best practices for a comprehensive email authentication policy?

Email authentication may sound complicated, but once you understand the technology, the techniques are easy to use. As good as SPF, DKIM, and DMARC are at protecting your domain, they don’t catch everything, but there are things you can do to expand your coverage. Start with BIMI.

What is BIMI, and how does it apply to authentication?

Your company logo is crucial to your brand’s image. Without it, no one would recognize you or your products. With the Brand Indicators for Message Identification (BIMI) protocol, your company can attach your logo to your emails. BIMI isn’t a policy anyone can use; it requires that your emails be authenticated.

Using BIMI happens after your email server reaches DMARC compliance, thereby adding a fourth layer of security to your server to help authenticate email. When users see your logo next to your message, they know they can safely access your content. BIMI doesn’t replace any of the other methods, but using all four creates a stronghold that protects you and your client’s data.

Keep training your employees

When you hire a new employee, you want to know how they can help your business meet your goals. You assume they will grow and adapt as your business needs change, but this is not always the case. Your employees may require additional training. The same goes for committing to better email authentication practices.

To learn a new skill and adapt to company changes, sometimes your employees need ongoing training. When trying to protect sensitive data, it’s best to provide educational opportunities for your employees to learn the best email security practices in the industry. They should be able to recognize cybercriminal activity and point out potential flaws in the system.

If they receive messages from an unknown sender, they shouldn’t click on any links or provide any private information to the sender. They should also practice better login standards by keeping their passwords safe and hidden while using company email.

Enable 2FA for your server

There are many online services that use your personal information for login credentials. If you aren’t setting up strong passwords, then your business is at a disadvantage. Fortunately, anyone can enable two-factor authentication (2FA) for their server.

If you shop on Amazon or use Google Workspace, then you’re already familiar with 2FA. Enabling 2FA is easy and is generally the same anywhere you can use it. Sometimes, when logging into your account, the service will ask if you want to set up 2FA.

You can enable 2FA by sending a code to your mobile device after you log in. Without entering the code, your account is locked and inaccessible by anyone. Using this method as a deterrent to cybercrime is always recommended if it’s available.

Utilize SSO for easier logins

Genuine trust is a hard-won benefit that not everyone gets to enjoy. If your business is a larger organization, it’s best to enable a Single Sign-On (SSO) service provider to assist with email security. SSO is like 2FA in the idea that it changes how you can log in to your email server.

While 2FA adds another step to the login process, and makes it more complex, SSO simplifies the process by using a trusted source. This trusted source handles and identifies personal authentication needs when users access your server. Servers that use SSO can verify a user’s identity with Security Assertion Markup Language (SAML).

With SAML, users can access several applications with one profile login. Corporations like Apple and Google use SSO to manage their applications for better control.

Use encryption for SMTP

As mentioned earlier, Simple Mail Transfer Protocol (SMTP) on its own isn’t secure and can be easily exploited, but you can protect your email's pathways by using encryptions. These encryptions will use certificates to pass along information through the pathway. If your information is intercepted, a hacker will have a difficulty deciphering the data due to the encryptions.

The central encryption that most SMTP servers use is Transport Layer Security (TLS), formerly Secure Sockets Layer (SSL), which optimizes delivery and encrypts the information so it can’t be stolen. Encryptions like this use opportunistic TLS, which encrypts everything going through the SMTP pathways.

How your organization can monitor email authentication practices

If your company enables better authentication practices, observing how your changes are affecting email deliverability is best. Most email services have tools to monitor and analyze authentication. If you’re considering SPF, DKIM, DMARC, and BIMI, each method uses DNS records containing instructions on the components and reports containing performance data.

With a DNS tool, you can check your records, update them as needed, and confirm they are correct. In terms of reporting, DMARC reports can monitor the results of your messages. The information is available as XML reports and is sent to the email address in your DMARC record.

Since DMARC needs SPF and DKIM to function, the XML reports also contain SPF and DKIM results data. These reports are also useful for identifying problem areas that may require troubleshooting. Sometimes, you may encounter issues like invalid DKIM signatures or missing DNS records.

You can do more by optimizing your server’s deliverability and reputation. Optimizations can be gradual increases in DMARC enforcement or implementation of TLS policies. Regardless of the precautions you take, it will require constant monitoring and diligence.


Your reputation is your lifeline. Without trust, your business will suffer as your former clients find a business that takes their privacy seriously. When your emails are properly authenticated using the industry’s best practices, your sender reputation will flourish.

At Liquid Web, we realize the importance of guaranteed email deliverability and keeping hackers at bay. Throughout 25 years in the business, Liquid Web has learned that email security cannot be overstated, and your server deserves a reliable security solution. Customized hosting options are offered here that safeguard your personal information from cybercrime.

If you’re looking for an industry partner who help you enable relevant practices to authenticate email, contact us today to learn more about our services.

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