SPF, DKIM, DMARC: Why Cold Emails Need Them

Cold email still works. It helps you reach prospects, spark leads, and grow outreach, without much cost. But hitting the inbox is harder now. Email service providers have indeed become stricter, especially when it comes to security and deliverability. Without the proper email authentication, your emails are likely to be blocked or flagged. To make cold email work today, you need a solid technical setup, and authentication is key

What is Email Authentication?

Email authentication proves that your message really comes from you. When you set up the right records, email services can check if your domain is real and hasn’t been faked. This helps your message get to the inbox and blocks people from pretending to be you.

For cold email, this setup is a must. If you skip it, your emails are more likely to land in spam or never get delivered. But with it in place, your messages are more likely to reach real people, keep your domain in good standing, and open the door to actual replies.

Why Does Email Authentication Exist?

 Prevent Spoofing

Cold email is already a delicate move; you’re reaching out to someone who doesn’t know you. Without authentication, others can fake your domain. Hurting trust with filters and people. Adding authentication like SPF, DKIM, and DMARC shows it's real and secure.

Protect Reputation‍

Your domain is your brand’s identity. Without proper email authentication, it damages your reputation, erodes trust, and can hurt your deliverability. Authenticate your domain to protect your name and credibility.

Improve Deliverability‍

Internet service providers (ISPs) trust authenticated senders. If your cold emails aren’t authenticated, they’ll likely be filtered or blocked.

Key Email Authentication Protocols

Sender Policy Framework

SPF (Sender Policy Framework) is a simple DNS record that instructs mail servers which IP addresses may send emails on your domain. Without one, anyone can spoof your domain, damaging your reputation and deliverability. The usual steps are to log into your domain registrar, locate the area of the DNS management, create a TXT record, and enter the correct SPF record syntax. This assists spam filters in verifying your emails are authentic and minimizes the likelihood they'll be marked or blocked. In cold outreach, SPF isn't just an option; it's a requirement.
Here’s the steps on how to set up the SPF:
1. Identify all email service providers that send email on behalf of your domain.
2. Write Your SPF Record
Example
v=spf1 ip4:192.0.2.0 ip4:192.0.2.1 include:examplesender.email -all
3. Log in to your domain registrar or DNS provider.
4. Add a TXT Record
Type: TXT
Name/Host: @ or your root domain (e.g., example.com)
Value: Your full SPF record (from step 2)
5. Save the record and wait for DNS propagation, which usually completes within a few minutes to 48 hours.

DomainKeys Identified Mail

DKIM or DomainKeys Identified Mail puts a digital signature on every email you send. That signature shows the message came from you and wasn’t altered on the way.

Spam filters and email services check DKIM to confirm the message is valid and intact. If the signature is missing or broken, your email can look suspicious, even if it’s real. That damages deliverability and encourages more spam.
Create a private and public key using your email service provider. Your private key signs your messages. Install the public key in the DNS of your domain. Receiving servers use it to ensure that the message is actually from you and remains unaltered.

Domain-based Message Authentication, Reporting, and Conformance

DMARC means Domain-based Message Authentication, Reporting, and Conformance. It helps block fake emails that claim to come from your domain. It works with SPF and DKIM, telling mail servers what to do if a message fails those checks. DMARC provides reports that show who is sending email using your domain.
Without DMARC, someone can send messages that look like they came from you, causing damage to your reputation, which can push your emails to spam.

Here are the steps on how to set up the DMARC:

1. Make sure SPF and DKIM are already set up. DMARC depends on both.

2. Create a DMARC policy. Choose what should happen to unauthenticated emails:

none (monitor only)

quarantine (send to spam)

reject (block it entirely)

3. Add a TXT record to your DNS. A basic record looks like this:
Name: _dmarc.yourdomain.com 
Type: TXT 
Value: v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com  

Start with p=none to collect insights without blocking emails. Once confident, move to quarantine or refuse to actively stop spoofing.

4. Monitor reports and use the data to spot abuse and fine-tune your settings.

Final Thoughts

SPF, DKIM, and DMARC do more than mark off a technical step; they protect your domain. It's critical infrastructure for cold email success. If you're committed to reaching the inbox, treat email authentication as a high priority. Configure your DNS records prior to deploying your cold email campaigns. Check your DMARC reports frequently to stay one step ahead of problems.
Email authentication doesn’t need to slow you down. Mailpool sets up SPF, DKIM, and DMARC for you, protecting your domain, improving deliverability, and letting you work faster without doing it yourself.