SPF for Constant Contact: Email Authentication Setup Guide

Constant Contact is one of the most popular email marketing platforms for small businesses. If you're sending newsletters, promotional campaigns, or event invitations through Constant Contact, setting up SPF helps ensure those emails land in your subscribers' inboxes rather than their spam folders.

For a comprehensive overview of SPF, see our complete SPF guide. This guide walks you through the setup process, explains Constant Contact's self-authentication feature, and covers common mistakes to avoid.

How Constant Contact Sends Your Emails

When you send a campaign through Constant Contact, the email doesn't come directly from your mail server. It's sent from Constant Contact's infrastructure on your behalf. Receiving email servers see the email coming from a Constant Contact IP address, not from your domain's servers.

Without SPF, receiving servers have no way to confirm that you authorized Constant Contact to send email for your domain. That's where your SPF record comes in — it explicitly tells the world that Constant Contact's servers are allowed to send email on behalf of your domain.

The Constant Contact SPF Include

The correct SPF include for Constant Contact is (Constant Contact Knowledge Base):

include:spf.constantcontact.com

This single include authorizes all of Constant Contact's sending servers to deliver email for your domain. You don't need to list individual IP addresses — the include covers Constant Contact's full infrastructure.

Setting Up SPF for Constant Contact

Constant Contact's Self-Authentication Feature

Constant Contact offers a built-in self-authentication feature that can handle much of the email authentication process for you. Here's how it works.

When you add and verify your domain in Constant Contact's account settings, Constant Contact configures authentication on their side. This includes:

• Return-path alignment — Constant Contact manages the bounce address, which is what SPF actually validates against
• DKIM signing — Constant Contact can sign your emails with DKIM if you add their CNAME records to your DNS
• Domain verification — Proves to Constant Contact that you own the domain

To set up self-authentication:

1. Log into your Constant Contact account
2. Go to My Account or Account Settings
3. Find the "Domain Authentication" or "Self-Authentication" section
4. Add your sending domain
5. Constant Contact provides DNS records (typically CNAME records for DKIM)
6. Add those records to your DNS provider
7. Return to Constant Contact and verify

Self-authentication improves your deliverability, but adding the SPF include to your DNS record is still recommended. It provides an extra layer of authorization and helps with DMARC alignment if you're using a DMARC policy. Understanding the difference between softfail and hardfail will help you choose the right enforcement level.

Common Constant Contact SPF Mistakes

Creating a second SPF record

This is the most common mistake. If you already have an SPF record for your email provider (like Google Workspace or Microsoft 365), don't create a separate one for Constant Contact. Two SPF records on the same domain cause a PermError, which breaks authentication for all your email — not just Constant Contact.

Wrong — two separate records:

v=spf1 include:_spf.google.com ~all
v=spf1 include:spf.constantcontact.com ~all

Correct — one combined record:

v=spf1 include:_spf.google.com include:spf.constantcontact.com ~all

Using the wrong include domain

Make sure you use spf.constantcontact.com exactly. Common typos include:

• constantcontact.com (missing the spf. prefix)
• spf.constant-contact.com (adding a hyphen)
• include:constantcontact.com (wrong subdomain)

The correct value is include:spf.constantcontact.com.

Forgetting to remove old entries

If you previously used a different email marketing platform and have switched to Constant Contact, remove the old platform's include from your SPF record. Every include takes up one of your 10 DNS lookups, and keeping old entries wastes that budget.

Not completing domain verification in Constant Contact

Adding the SPF include to your DNS is only half the process. You should also complete Constant Contact's domain verification so they can properly align your emails for authentication. Without it, Constant Contact may use their own domain in the Return-Path, which means the SPF check validates against their domain, not yours.

Constant Contact with Other Email Services

Most businesses use Constant Contact for marketing emails alongside a primary email provider for day-to-day communication. Here are common combinations:

Constant Contact + Google Workspace:

v=spf1 include:_spf.google.com include:spf.constantcontact.com ~all

Constant Contact + Microsoft 365:

v=spf1 include:spf.protection.outlook.com include:spf.constantcontact.com ~all

Constant Contact + Google Workspace + Zoho CRM:

v=spf1 include:_spf.google.com include:spf.constantcontact.com include:zoho.com ~all

As you add more services, watch your DNS lookup count. Each include adds lookups toward the limit of 10. If you're getting close, see our guide on what to do when your SPF record gets too long. Need help building the right record? SPF Creator can generate the correct syntax for your combination of services.

Complete Email Authentication for Constant Contact

SPF is just one part of a complete email authentication setup. For the best deliverability with Constant Contact, you should have all three protocols in place:

SPF — Add include:spf.constantcontact.com to your SPF record (what this guide covers).

DKIM — Complete Constant Contact's self-authentication to enable DKIM signing. This adds a cryptographic signature to your emails that receivers can verify.

DMARC — Once SPF and DKIM are working, add a DMARC record to tell receiving servers how to handle emails that fail authentication. Start with p=none to monitor, then move to stricter policies.

Together, these three protocols protect your domain from being spoofed and significantly improve your inbox placement rates.

Verifying Your Setup

After configuring everything, make sure it's working:

1. Check your SPF record with the tool above. Confirm it's valid, includes spf.constantcontact.com, and stays under 10 DNS lookups.
2. Check Constant Contact's verification status. In your account settings, your domain should show as verified or authenticated.
3. Send a test campaign. Send a test email to a Gmail address. Open it, click the three dots, select "Show original," and look for spf=pass and dkim=pass in the Authentication-Results header.
4. Run a full deliverability check at Deliverability Checker to see your complete authentication status across SPF, DKIM, DMARC, and MX records.

Monitor Your SPF Records

Checking once is good. Monitoring continuously is better. The Email Deliverability Suite watches your SPF, DKIM, DMARC, and MX records daily and alerts you when something breaks.

References

• RFC 7208: Sender Policy Framework (SPF) — The current SPF specification
• Constant Contact: Self-Authenticate Your Email — Official Constant Contact authentication guide