How to fix missing dmarc on BigCommerce

Steps for BigCommerce

1. BigCommerce does not manage DNS directly. Go to your BigCommerce control panel → Store Setup → Domain Names to confirm whether your domain DNS is managed by BigCommerce (via Fastly/Cloudflare) or your own registrar.
2. If DNS is managed externally: log into your registrar's DNS dashboard, add a TXT record with Name = '_dmarc' and Value = v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com
3. BigCommerce sends transactional emails on your behalf. Navigate to Store Setup → Email Templates to review your sender address, then follow BigCommerce's Help Center guide for 'Email DNS Authentication' to add the SPF and DKIM records BigCommerce provides — these must pass before you enforce DMARC.
4. If you use a third-party ESP (Klaviyo, Mailchimp, etc.) connected via BigCommerce apps, configure SPF/DKIM in that ESP for your domain as well.

; DNS TXT record — hostname: _dmarc.yourdomain.com
; Phase 1 – monitoring only (safe starting point)
v=DMARC1; p=none; rua=mailto:dmarc@yourdomain.com

; Phase 2 – enforcement (after confirming all legitimate mail passes)
v=DMARC1; p=quarantine; rua=mailto:dmarc@yourdomain.com; pct=100

; Phase 3 – strictest (recommended long-term goal)
v=DMARC1; p=reject; rua=mailto:dmarc@yourdomain.com; pct=100

What is missing dmarc?

DMARC (Domain-based Message Authentication, Reporting & Conformance) is a free email authentication standard you publish as a DNS record. It tells the world's email providers — Gmail, Outlook, Yahoo, and others — what to do when someone sends an email that pretends to be from your domain but fails authentication checks. Without a DMARC record, anyone can forge your store's "From" address and send convincing phishing or spam emails that appear to come from you. The record lives at a specific DNS address (_dmarc.yourdomain.com) and takes effect within 24–48 hours of being added.

Without DMARC, criminals can send emails that look exactly like they came from your store — order confirmations, password resets, or fake promotions — tricking your customers into handing over payment details or passwords. This directly damages customer trust, can result in your domain being blacklisted by mail providers (destroying your legitimate email deliverability), and exposes you to legal and reputational liability under consumer-protection and data-privacy laws. OWASP classifies this as a Security Misconfiguration (A05:2021) — one of the most common and impactful categories of web security failures. Fixing it is free and takes under 30 minutes yet closes a major attack vector immediately.

See the complete Missing dmarc guide for every platform and the full background.