Improving Email Deliverability — SPF, DKIM & DMARC

Email deliverability is critical for your business communications. This guide explains how to configure DNS records that help your emails pass spam filters.

SPF (Sender Policy Framework)

SPF tells receiving mail servers which IP addresses are authorized to send email for your domain. Add this TXT record to your DNS zone:

v=spf1 +a +mx +ip4:YOUR_SERVER_IP ~all

DKIM (DomainKeys Identified Mail)

DKIM adds a digital signature to your outgoing emails. In Virtualmin:

1. Go to Email → DKIM
2. Click Enable DKIM Signing
3. Copy the generated TXT record and add it to your DNS zone

DMARC (Domain-based Message Authentication)

DMARC tells receiving servers how to handle emails that fail SPF or DKIM checks. A basic DMARC record:

v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.co.za

Start with p=none (monitoring mode) and move to p=quarantine or p=reject once you confirm all legitimate email is authenticating correctly.