Checking DMARC with Constant Contact

Constant Contact has been around longer than most ESPs in the small business space, and it's still a common choice for associations, non-profits and local businesses. Its DMARC story is a bit different from newer platforms: for years it signed mail with its own domain by default, and alignment with your own domain required manually enabling "self-authentication." If you inherited a Constant Contact account that was never reconfigured, your campaigns are almost certainly failing DMARC. Here's how to fix it.

What self-authentication actually does

By default, Constant Contact sends mail with a "From:" that looks like yours but a return-path and DKIM signature that belong to ccsend.com or similar Constant Contact domains. When DMARC checks run, nothing aligns with your From: domain and the message fails.

Self-authentication tells Constant Contact to sign mail with a DKIM key that belongs to your domain. Once enabled and verified, DKIM will align and DMARC will pass.

Step 1: Enable self-authentication

In Constant Contact, go to My Account → Advanced Settings → Self-Authentication → Enable. Enter the domain you send campaigns from (typically yourdomain.com).

Constant Contact will generate two CNAME records for DKIM, plus (depending on your plan and region) a TXT record suggestion for SPF. The CNAMEs look something like:

k1._domainkey.yourdomain.com   CNAME   dkim1.constantcontact.com
k2._domainkey.yourdomain.com   CNAME   dkim2.constantcontact.com

Step 2: Publish DNS records

Add both CNAMEs to your DNS provider exactly as shown. Some DNS interfaces auto-append the zone name — watch out for duplicated yourdomain.com.yourdomain.com.

After publishing, wait 15-30 minutes and click Verify in Constant Contact. If verification fails, use a DNS lookup tool to confirm the records resolve, then retry.

Step 3: Don't forget SPF (but don't overdo it)

Constant Contact historically worked without SPF changes, relying on DKIM for alignment. If you want SPF to align too, add their include:

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

For DMARC purposes, you only need one of SPF or DKIM to align. If your SPF record is already crowded, lean on DKIM and don't add the Constant Contact include.

Step 4: Verify DMARC alignment

Send a test campaign and inspect the headers. Look for:

dkim=pass header.d=yourdomain.com
dmarc=pass header.from=yourdomain.com

If header.d still shows a Constant Contact domain, self-authentication isn't fully active — double-check the CNAMEs resolved and you clicked Verify.

Step 5: Check your DMARC record

Validate your published DMARC record with the free DMARC record checker. A safe starter record for a Constant Contact user moving toward enforcement:

v=DMARC1; p=quarantine; pct=50; rua=mailto:[email protected]

The pct=50 means only half of failing mail is quarantined — useful while you validate that self-authentication is working across all campaigns. Once reports look clean, drop pct and move to p=reject if appropriate. dmarccreator.com can build these records for you step by step.

Common Constant Contact DMARC issues

Multiple sending domains

Constant Contact allows multiple verified email addresses across different domains. Each unique domain you send from needs its own self-authentication setup. An association with [email protected] and [email protected] needs two sets of CNAMEs.

Non-profits and DMARC

Constant Contact is very popular with non-profits, and many non-profit domains never had DMARC at all. The upgrade path is:

1. Enable self-authentication in Constant Contact
2. Publish a starter DMARC record at p=none with reporting
3. Watch reports for 2-4 weeks
4. Move to p=quarantine once clean
5. Monitor continuously with deliverabilitychecker.com

Long-term monitoring

Once DMARC is set up, the goal is to keep it that way. DKIM keys can rotate, DNS changes happen, and new sending tools get added without anyone remembering to authenticate them. Continuous monitoring closes that gap.