Email Deliverability & DMARC Checker. Stop domain spoofing.
Audit SPF syntax, DMARC policies, MX mail servers, DKIM selectors, and anti-spam blacklists. Get an immediate score and copy-pasteable DNS fix records.
Frequently Asked Questions
Why is DMARC enforcement critical for every business domain?
DMARC (Domain-based Message Authentication, Reporting, and Conformance) prevents cybercriminals and spammers from sending unauthorized emails that appear to originate from your exact domain address. Without a strict DMARC policy ('p=reject' or 'p=quarantine'), anyone can impersonate your brand in phishing or CFO fraud attacks. Major inbox providers like Google and Yahoo now require valid DMARC authentication for inbox delivery.
What is the SPF 10 DNS lookup limit, and why does it fail?
The SPF specification (RFC 7208) imposes a hard limit of 10 DNS lookups per SPF check to prevent Denial of Service attacks. Each 'include:', 'a', 'mx', and 'redirect' mechanism counts as a lookup. If your SPF record includes too many third-party services (e.g. Google, Microsoft, Hubspot, SendGrid, Zendesk), receivers stop evaluating SPF, resulting in deliverability failures.
What does an invalid DMARC record look like?
A common domain configuration mistake occurs when an administrator mistakenly creates a TXT record at _dmarc.domain containing an SPF string ('v=spf1 ...') instead of a DMARC policy ('v=DMARC1; p=reject; ...'). Receiving mail servers treat this as an invalid DMARC record, leaving the domain completely vulnerable to spoofing.
How is the 0–100 Deliverability Score calculated?
The score evaluates 5 key dimensions: DMARC Policy & Alignment (30%), SPF Validity & Lookup Limits (25%), MX Config & Provider Security (20%), DKIM Selector Deployment (15%), and Anti-Spam Blacklist Status (10%). Grades range from A+ (92+) down to F (<40).
Is it safe to check a competitor's domain?
Yes. The tool queries public DNS records (MX, TXT, DMARC, DKIM) and public anti-spam IP blacklists. It sends zero email traffic and makes no intrusive connections.
Need Help Hardening Your Email Infrastructure?
TxLabz engineers handle full email authentication deployment, custom DMARC monitoring setups, and domain deliverability repair for companies that rely on email revenue.