Enter up to 10 domains (or email addresses) below to audit their live MX servers, SPF authorization, DMARC policy, and DNSBL blacklist status side-by-side—or drop your full CSV/Excel lead list below to verify every mailbox via Smart SMTP.
Paste one domain or email per line (or comma-separated):
Valid domain MX records only prove the company exists—not the employee mailbox. Pre-scan your list + test 5 emails via live Smart SMTP free.
Before launching an account-based marketing (ABM) campaign or importing a new partner lead list, auditing the underlying recipient and sender domains reveals whether those organizations actually operate healthy mail servers. Our Email Domain Checker inspects up to 10 domains simultaneously in parallel.
For each domain entered, the engine resolves authoritative NS and MX records, identifies the inbound mail gateway (Google Workspace, Microsoft 365, Proofpoint, Mimecast, Yahoo/Ymail, Zoho, or Proton), audits v=spf1 and _dmarc enforcement policies, and checks whether the domain is flagged in our 112,000+ disposable email registry.
| Domain Diagnostic Dimension | DNS & Network Telemetry Inspected | Why It Matters for B2B Outreach |
|---|---|---|
| Inbound MX Gateway Fingerprint | MX priority, hostname pattern & TLS banner | Identifies strict enterprise filters (Proofpoint/Mimecast) before sending |
| SPF & DMARC Security Posture | v=spf1 lookup count + _dmarc policy (none/quarantine/reject) | Measures domain maturity and anti-spoofing enforcement |
| Disposable & Parked Domain Check | 112,000+ DEA registry + Null MX (RFC 7505) detection | Prevents mailing dead, parked, or throwaway burner domains |