DKIM, SPF, DMARC for CRM Emails

If your CRM emails aren't authenticated, they may end up in spam folders - or worse, not delivered at all. SPF, DKIM, and DMARC are essential email authentication protocols that ensure your messages are verified and secure. Here's a quick breakdown of how they work:

• SPF: Authorizes specific servers to send emails on your behalf (like a guest list).
• DKIM: Confirms your email content hasn't been altered (like a tamper-proof seal).
• DMARC: Enforces SPF and DKIM and tells servers what to do if authentication fails.

Starting February 2024, major providers like Google and Yahoo will require these protocols for bulk emails, making them more critical than ever for CRM success. Proper implementation can boost CRM email deliverability by up to 10% and reduce phishing risks by 80–90%.

Key Steps to Get Started:

1. Identify all email-sending systems (e.g., Google Workspace, Salesforce, Mailchimp).
2. Configure SPF, DKIM, and DMARC in your DNS records.
3. Monitor results and adjust policies to ensure alignment and enforcement.

Neglecting these protocols could mean your emails never reach inboxes. Take action today to protect your domain and improve deliverability.

What Are SPF, DKIM, and DMARC?

SPF, DKIM, and DMARC are protocols stored as TXT records in your DNS that work together to ensure your CRM emails are authenticated. Here's how they function: SPF verifies the servers allowed to send emails on your behalf, DKIM ensures the content of your emails remains intact, and DMARC enforces alignment between the sender's domain and authentication results.

When your CRM sends an email, services like Gmail or Outlook check these TXT records to confirm the email's legitimacy. SPF ensures the sending server is authorized, DKIM verifies that the message content hasn’t been tampered with, and DMARC ties it all together by requiring the "From" address to match the authenticated domain. This layered system is highly effective - proper implementation of these protocols can reduce phishing attacks by 80–90%, a critical measure given that phishing was behind 85% of all cyberattacks in 2022. Let’s break down how each of these protocols works to safeguard your emails.

SPF: Authorizing Email Servers

SPF (Sender Policy Framework) is like a guest list for your domain’s emails. It’s a DNS TXT record that specifies which servers are allowed to send emails on your behalf. To avoid delivery issues, make sure your SPF record includes your CRM platform’s sending servers.

One thing to keep in mind: SPF records are limited to 10 DNS lookups. If you’re using multiple services - say Google Workspace, Salesforce, and Mailchimp - you could hit this limit quickly, leading to authentication failures. Planning your SPF record carefully is key to avoiding these issues.

DKIM: Verifying Email Content

DKIM (DomainKeys Identified Mail) focuses on email integrity. It uses cryptographic keys to confirm that your email content hasn’t been altered during transit. Here’s how it works: your CRM signs outgoing emails with a private key, and receiving servers use a public key (published in your DNS) to verify the signature.

To minimize the risk of spoofing and avoid common DKIM setup errors, use 2048-bit RSA keys and rotate them every 6–12 months. This ensures your keys remain secure and hard to exploit.

DMARC: Enforcing Authentication Policies

DMARC (Domain-based Message Authentication, Reporting, and Conformance) ties everything together. It combines the results of SPF and DKIM and tells receiving servers what action to take if an email fails authentication. You can choose to monitor emails, send them to spam (quarantine), or reject them outright.

DMARC also generates reports that provide insights into your email authentication results. However, for DMARC to work effectively, the domain in the "From" header must match the domain authenticated by SPF or DKIM. A major challenge is that 75–80% of domains with DMARC records don’t achieve full enforcement, often because they haven’t identified all legitimate sending sources.

"DMARC is not just a record, it's a process of organizing your email program to keep spoofers from impersonating you." - Mailgun

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Preparing Your Domain for Email Authentication

Before diving into DNS record updates, it's crucial to identify every system that sends emails on behalf of your domain. Skipping this step is a major reason why an estimated 75% to 80% of domains with DMARC records fail to achieve full enforcement. A detailed audit now can save you from deliverability headaches later. Here's how to map out senders, check your DNS records, and pick the best domain setup for your CRM emails.

List All Email-Sending Systems

Start by documenting every platform or service that sends emails from your domain. This could include:

• Productivity tools like Google Workspace or Microsoft 365
• CRM platforms such as Salesforce or HubSpot
• Marketing tools like Mailchimp
• SMTP relay services such as Mailgun or SendGrid
• Web server contact forms
• On-premises Exchange servers
• Automated notifications from various applications

If you're not sure you've captured everything, setting your DMARC policy to p=none can help. This generates aggregate reports (RUA) that list all IP addresses and servers sending emails on behalf of your domain, making it easier to spot overlooked systems. Additionally, tools like MxToolbox or DMARCian can help you review your current DNS setup and identify any legacy systems still authorized to send emails.

Review Your Current DNS Records

Once you've listed all email-sending systems, it’s time to verify your DNS records. Use commands like nslookup -type=txt yourdomain.com (Windows) or dig yourdomain.com txt (Mac/Linux) to view TXT records tied to your domain.

Pay special attention to your SPF record. There should be only one SPF record for your domain - having multiple records can cause authentication failures. If needed, avoid common misconfigurations by consolidating them into a single string, such as:
v=spf1 include:_spf.google.com include:mailgun.org -all.

Also, remember that SPF records are limited to 10 DNS lookups. Going over this limit will break authentication entirely. If you’re close to the limit, consider simplifying your SPF record or using subdomains to distribute lookups.

Select a Domain or Subdomain for CRM Emails

Consider using a dedicated subdomain (e.g., crm.yourdomain.com or outreach.yourdomain.com) for CRM-related emails. This approach helps protect your main domain's reputation. For instance, if a marketing campaign triggers spam complaints, it won’t impact critical business emails sent from your primary domain.

Subdomains also come with their own 10-lookup SPF allowance, which makes managing multiple sending services easier. Just make sure the domain in the "From" address of your emails aligns with the domain that has valid SPF and DKIM records. For example, if you’re using a subdomain, your "From" address should look something like info@crm.yourdomain.com, and it must be properly configured for DMARC alignment.

How to Configure SPF, DKIM, and DMARC

Now that you've reviewed your email-sending systems and DNS records, it's time to dive into configuring the three key email authentication protocols. Here's how to get them set up correctly for your CRM emails.

Setting Up SPF Records

Start by getting the SPF values from your SMTP relay provider. For instance, Mailgun uses include:mailgun.org, and SendGrid provides include:sendgrid.net. If you're using a platform like Google Workspace or Microsoft 365, they’ll also have specific SPF values to include.

In your DNS settings, create a single TXT record with the format:
v=spf1 include:[provider_domain] -all.

For example, if you’re using both Microsoft 365 and Mailgun, your combined record would look like this:
v=spf1 include:spf.protection.outlook.com include:mailgun.org -all.

When configuring SPF for the first time, it’s a good idea to use ~all (soft fail) instead of -all (hard fail). This lets you monitor email delivery without blocking legitimate emails right away. Once you’ve verified that all email sources are listed correctly, switch to -all for stricter enforcement. This technical setup is a critical part of a broader email deliverability checklist for maintaining high inbox placement.

Keep in mind that SPF records are limited to 10 DNS lookups. If you’re nearing this limit, replace some "include" statements with direct IP addresses using the ip4: or ip6: mechanism. After publishing the TXT record, verify it using tools like MXToolbox or Google Admin Toolbox to ensure it’s live and error-free. DNS changes typically propagate within 15–30 minutes but may sometimes take up to 24 hours. Once verified, you’re ready to move on to DKIM.

Configuring DKIM Authentication

DKIM relies on a pair of cryptographic keys: a private key stored on your SMTP server to sign outgoing emails and a public key published in your DNS for recipients to verify those signatures. Start by accessing your CRM or SMTP relay dashboard to generate these keys. Your provider will also assign a selector, which is a unique identifier like "dkim", "mail", or even something date-based like "2024sep". This allows you to manage multiple keys for different services on the same domain.

Your provider will give you either a TXT record or CNAME records to add to your DNS. For TXT records, the host name usually follows this format:
[selector]._domainkey.yourdomain.com

The value will contain your public key, formatted like this:
v=DKIM1; k=rsa; p=[PublicKey].

Some providers, like Microsoft 365, prefer CNAME records (e.g., selector1._domainkey) because they allow automatic key rotation without requiring manual DNS updates. Always choose 2048-bit RSA keys for stronger security over the older 1024-bit keys. Once the DNS changes propagate, enable DKIM signing in your provider’s settings.

To verify your DKIM setup, send a test email to a service like mail-tester.com or use a DNS lookup tool to confirm that the record is valid. For full DMARC compliance, ensure the DKIM signing domain (in the d= tag) matches the domain in your "From" address.

"DKIM is fundamental in protecting your email recipients and senders from malicious communication, forged messages, phishing, and spoofing attempts." – EasyDMARC

With SPF and DKIM in place, you’re ready to configure DMARC for enforcing your authentication policies.

Implementing DMARC Policies

DMARC works by combining SPF and DKIM results and instructing receiving servers on how to handle emails that fail authentication. Start with a monitoring policy by creating a TXT record at _dmarc.yourdomain.com. Use the following value:
v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com.

The p=none policy lets you collect data without blocking emails, while the rua tag directs aggregate reports to your specified email address. Monitor these reports for 2–4 weeks to confirm that your CRM emails are passing authentication. Once you’re confident everything is aligned, gradually enforce stricter policies. Start with p=quarantine to send failing emails to the spam folder, and eventually move to p=reject to block them entirely.

If you’re concerned about disrupting legitimate traffic, use the pct tag (e.g., pct=25) to apply stricter policies to only a portion of your email volume during testing.

"The end goal is ideally a policy of p=reject. That's what DMARC is for. Ensuring that your domain cannot be spoofed and protecting our mutual customers from abuse." – Marcel Becker, Senior Director of Product, Yahoo

Enforcing DMARC can reduce phishing attempts against your domain by 80–90%. It can also improve email delivery rates by up to 10%. However, about 75% to 80% of domains with a DMARC record fail to reach full enforcement, often because they skip the monitoring phase or miss identifying all email-sending systems. Taking the time to configure SPF, DKIM, and DMARC properly will protect your domain’s reputation and help ensure your CRM emails reach your recipients’ inboxes.

Troubleshooting Common Authentication Problems

Even after setting up SPF, DKIM, and DMARC, authentication problems can still block your CRM emails from reaching inboxes. Without proper authentication, 46% of emails fail to land in recipients' inboxes.

Fixing SPF Lookup Errors

SPF errors often stem from exceeding the lookup limit. Each mechanism like include, a, mx, ptr, or exists triggers a DNS lookup, and if your record exceeds 10 lookups, SPF fails entirely. This can lead to your emails being marked as unauthenticated.

To address this, start by auditing your SPF record using tools like MXToolbox or Red Sift. Remove outdated "include" statements for services you no longer use. Replace excessive include mechanisms with direct IP addresses (e.g., ip4: or ip6:), as these don't count toward the 10-lookup limit. For instance, instead of include:mailgun.org, you could use ip4:192.168.0.1.

Another helpful tactic is using subdomains to separate email streams. Assign marketing emails to marketing.yourdomain.com and transactional emails to transactional.yourdomain.com, each with a simplified SPF record.

Ensure there's only one SPF record for your domain. If multiple TXT records start with v=spf1, servers will treat all of them as invalid. Combine entries into a single record, like this: v=spf1 include:_spf.google.com include:mailgun.org ~all.

"The SPF protocol also has a limit of 10 DNS lookups, where only the first 10 lookups in your SPF record will be actioned. If the email is not matched within these 10 lookups, it will be treated as unauthenticated." – Cameron Henry, Enterprise Technical Account Manager, Sinch Mailgun

Lastly, ensure your PTR record matches your forward DNS exactly. Keep in mind that DNS changes can take anywhere from 15 minutes to 48 hours to propagate.

Resolving DKIM Failures

DKIM issues often result from selector mismatches or DNS misconfigurations. When an email is sent, the DKIM signature includes a selector (e.g., default._domainkey) that tells the receiving server where to find the public key in your DNS. If this selector doesn’t match the one in your DNS, authentication fails.

To troubleshoot, review email headers (in Gmail, use "Show original") to check DKIM results. Look for dkim=pass or dkim=fail, along with error details. Common problems include incorrect selector names, DNS records that haven’t propagated, or public keys that were truncated when split across multiple lines by your DNS provider.

Key rotation mismatches are another frequent issue. If your DNS public key is updated but the email server still uses the old private key (or vice versa), signatures won’t validate. Always update both keys together and switch to 2048-bit RSA keys for stronger security. Be aware that email forwarding services or security tools that modify headers or add footers can break DKIM signatures. To minimize risks, use separate selectors for different email streams, such as marketing._domainkey and transactional._domainkey.

You can verify your DKIM setup using tools like MXToolbox, MailTested, or EasyDMARC. These services confirm if your public key matches the email signature and whether the signing domain (d= tag) aligns with your "From" address.

Addressing DMARC Alignment Issues

DMARC alignment problems occur when the domain in your visible "From" address doesn’t match the domain used in SPF (Return-Path) or DKIM (d= tag). For an email to pass DMARC, either SPF or DKIM must succeed with proper alignment. If both fail or are misaligned, the DMARC policy will determine whether the email is quarantined or rejected.

A common issue is with third-party services that use their own domains for bounce handling. For instance, if your "From" address is sales@yourdomain.com but the Return-Path is bounce@third-party-service.com, SPF alignment will fail. Work with your CRM or email provider to set a custom Return-Path that matches your domain.

For DKIM alignment, ensure your email server or third-party service is signing emails with a key tied to your domain, not theirs. Check the DKIM signature's d= tag in the headers - it should match the domain in your "From" address.

DMARC aggregate reports are invaluable for diagnosing alignment issues. These reports, sent to the address in your rua tag, show which IPs are sending on your behalf and whether they pass or fail authentication. Use them to identify overlooked sources like billing systems, contact forms, or legacy applications that need to be added to your SPF record or configured with DKIM.

Begin with a monitoring policy (p=none) for at least 30 days to gather data without impacting delivery. After resolving alignment issues, gradually move to stricter policies like p=quarantine and then p=reject. Organizations that enforce DMARC see a 5–10% increase in delivery rates and an 80–90% reduction in phishing attempts.

Monitoring Email Deliverability with Warmforge

Setting up SPF, DKIM, and DMARC is just the beginning. DNS records can fail silently, and when that happens, your CRM emails might end up in spam folders - even if your dashboard shows a "delivered" status. Remember, "delivered" only means the server accepted the email; it doesn’t guarantee it reached the primary inbox. Without proper authentication and a solid sender reputation, your emails could still land in spam or promotions. That’s where monitoring tools come into play.

Tools for Tracking Email Deliverability

Warmforge offers automated monitoring to catch these silent issues before they harm your sender reputation. One standout feature is its inbox placement tests, which show exactly where your emails are landing - whether it’s the primary inbox, promotions, or the dreaded spam folder. Plus, you get one free placement test every month.

Keeping an eye on your DNS records is key to maintaining the deliverability improvements achieved through SPF, DKIM, and DMARC. Warmforge scans your DNS records daily and notifies you of any misconfigurations. It also includes blacklist monitoring to ensure your domain and IP addresses stay off spam databases.

"Deliverability is a measure of the health of your email marketing program, so it's important to do regular check-ups on your domain, IP, and authentication in particular to make sure you're up-to-date." – Carin Slater, Manager of Lifecycle Email Marketing, Litmus

How Warmforge Improves CRM Email Performance

Warmforge goes beyond monitoring by offering automated warm-up services to boost deliverability. This feature helps establish the sending history that inbox providers like Gmail and Outlook look for. Using AI to simulate human interactions - such as opening, replying, and marking emails as important - Warmforge helps these providers trust your domain. This is especially helpful for new domains or mailboxes that haven’t yet built a reputation.

Even with perfectly configured authentication protocols, CRM campaigns benefit from Warmforge’s warm-up services, which improve inbox placement rates. To help users get started, Warmforge provides one free warm-up slot for a Google or Microsoft mailbox.

Warmforge also integrates seamlessly with the Forge Stack, a suite of tools designed to simplify email management. For example, Mailforge automates DNS setup, cutting down configuration time from hours to just minutes, while Primeforge handles Google Workspace and Microsoft 365 mailboxes. Together, these tools ensure your authentication settings, warm-up process, and deliverability monitoring work in harmony. Pricing starts at $9 per mailbox slot per month (billed annually), with discounts available for higher volumes, going as low as $3 per slot.

Conclusion

Getting SPF, DKIM, and DMARC set up is just the beginning of improving your CRM email deliverability. Keeping it all running smoothly takes ongoing effort. Start by authorizing your sending servers through SPF, adding a layer of security with DKIM, and enforcing your policies with DMARC. But don’t stop there - regularly reviewing and updating your email authentication setup is key, especially as your email infrastructure evolves.

As mentioned earlier, monitoring is a must. Without it, you risk legitimate emails failing authentication without even realizing it. Many domains struggle to fully implement DMARC enforcement because they don’t monitor closely enough to move from a “monitor-only” policy (p=none) to stricter enforcement safely.

"At its core, email authentication just requires some attention to detail and ongoing monitoring to catch issues as early as possible." - Margaret Wolfenden, Email Strategist, Validity

To take your efforts further, consider using reliable monitoring tools. While authentication establishes your identity, tools like Warmforge ensure your emails actually land in inboxes. With features like automated warm-up services, daily DNS monitoring, and monthly placement tests, Warmforge helps build and maintain the sender reputation that inbox providers expect. It proactively identifies misconfigurations that could hurt deliverability and even offers a free warm-up slot to get you started.

For optimal results, make it a habit to review your DMARC reports, regularly rotate your DKIM keys every 6 to 12 months, and incorporate tools like Warmforge into your strategy. These steps can make the difference between your emails landing in the inbox or getting lost in the spam folder.

FAQs

Why are SPF, DKIM, and DMARC important for CRM email deliverability?

SPF, DKIM, and DMARC are crucial tools for email authentication, ensuring that your messages are trusted by mailbox providers. Here's how they work: SPF checks which IP addresses are authorized to send emails on behalf of your domain. DKIM attaches a digital signature to your emails, verifying that they haven’t been altered during transit. DMARC ties it all together, enforcing authentication policies and offering reports to track any misuse of your domain.

CRM platforms often send large volumes of emails via shared SMTP relays. Without proper authentication, this can raise red flags with providers like Gmail or Outlook, potentially harming your email deliverability. Setting up these protocols correctly not only improves your inbox placement but also shields your domain from spoofing or phishing attacks, all while maintaining your sender reputation. With Warmforge’s AI-powered tools, you can monitor and fine-tune your SPF, DKIM, and DMARC configurations, ensuring your CRM emails consistently land in the primary inbox.

How do I fix SPF lookup errors in my DNS records?

To fix SPF lookup errors in your DNS records, start by running a deliverability test to uncover any SPF authorization issues. Tools like Warmforge can help you identify problems and provide detailed insights. Once you've pinpointed the issue, review the syntax of your SPF record in your DNS settings. Look for a TXT entry that begins with v=spf1, and double-check that all mechanisms are correctly formatted, spaced, and the record ends with either ~all (soft fail) or -all (hard fail). Even small typos or spacing mistakes can lead to failures.

Another common issue is exceeding the 10 DNS lookup limit for SPF records. If this happens, simplify your record by consolidating multiple include: statements, replacing them with specific IP ranges, or removing outdated mechanisms. Once you've made the necessary adjustments, publish the updated record in your DNS zone and wait for it to propagate. Afterward, run another test to ensure the problem is resolved. To avoid future issues, consider using automated monitoring tools like Warmforge, which can alert you to changes that might cause errors.

How can I fully enforce DMARC to protect my email domain?

To implement full DMARC enforcement, create a DMARC TXT record in your DNS with the policy set to p=reject and pct=100. Make sure your SPF and DKIM records are correctly configured and aligned with your domain. Also, activate aggregate and forensic reporting to keep track of email activity and verify that unauthenticated messages are being blocked as intended. This approach not only safeguards your domain against spoofing but also enhances email deliverability.

Related Blog Posts

• Why Emails Go to Spam: 5 Common Causes
• SPF vs DKIM vs DMARC: Key Differences
• DKIM, SPF, DMARC: SMTP Authentication Basics
• Google Workspace: Anti-Spoofing Setup Guide