The 4 Essential DNS Records for 100% Inbox Placement
Setting up cold email sending domains incorrectly is the #1 reason outbound campaigns land in the spam folder or trigger immediate domain burns. Here is the exact technical breakdown of the required DNS records:
1. SPF (Sender Policy Framework)
SPF informs receiving mail servers which IP addresses are authorized to dispatch messages from your domain. For Microsoft Azure and Heyo Infra sending, a proper SPF record is formatted as:
v=spf1 include:spf.protection.outlook.com -all2. DKIM (DomainKeys Identified Mail)
DKIM creates an immutable cryptographic signature attached to every outbound email header. When the recipient server validates this signature against your public DNS key, it verifies that the email was not spoofed or modified in transit.
3. DMARC Policy
DMARC provides instructions to inbox providers on how to handle emails that fail SPF or DKIM checks. In 2026, a valid DMARC record is mandatory for all cold email domains:
v=DMARC1; p=none; rua=mailto:dmarc-reports@yourdomain.com; pct=100;4. Custom Tracking Domains (CNAME)
Using shared tracking domains provided by sending tools flags your links as spam. A dedicated CNAME record (e.g. track.yourdomain.com) isolates your click and open tracking reputation entirely to your own domain.
Automating DNS with Cloudflare & Heyo Infra
Heyo Infra connects directly to Cloudflare and Spaceship APIs to provision and verify all 4 records in real-time, eliminating manual DNS errors and cutting domain setup time from hours to seconds.