VerifyPulse
Start Free
Free Deliverability Diagnostic

Domain SPF, DMARC & MX Health Inspector

Live authoritative DNS audit. Detects RFC 7208 10-lookup PermErrors, DMARC spoof vulnerabilities, and mail routing fallbacks.

Quick Test:
A+
stripe.com
Deliverability Health Score: 100/100
MX Records (Mail Exchanger)
Active (2 hosts)
stripe-com.mail.protection.outlook.com
SPF (RFC 7208 Depth)
Valid (1/10 lookups)
v=spf1 include:_spf.stripe.com ~all
DMARC Policy Enforcement
Protected (REJECT)
v=DMARC1; p=reject; pct=100

Deliverability & Spoof Protection Summary

  • All primary sending authentication records verified properly.
Need 0% bounce rate for cold outbound?
Browse audited B2B lead lists or test individual recipient emails.

Why Domain Deliverability Fails in 2026

Three hidden DNS pitfalls that trigger automated spam placement in Google Workspace and Microsoft 365.

Diagnostic #01

RFC 7208 10-DNS-Lookup Limit

Each include:, a, mx, or redirect directive in your SPF record consumes one DNS lookup. When total lookups exceed 10, receiving mail servers terminate evaluation with a permanent error (PermError), instantly dumping cold emails into spam.

Diagnostic #02

Google & Yahoo Mandatory DMARC

Under modern sender guidelines, bulk domains must publish an active DMARC policy. Domains configured with p=none are in passive monitoring mode and provide zero spoof protection, while domains missing DMARC are heavily throttled or rejected entirely.

Diagnostic #03

Authoritative MX Fallbacks

Sending emails from domains lacking live Mail Exchanger (MX) hosts causes immediate bounce flags. Receiving servers verify whether the sender domain can receive bounce notifications and return-path mail before accepting incoming messages.