Recipe

Check a list of domains for DNS, SPF and SSL problems

How do I check hundreds of domains for expiring certificates, broken SPF or a missing DMARC record?

Why the obvious route disappoints

Doing this by hand is a dig, a whois and an openssl call per domain, and the answers land in your terminal instead of in a table you can sort.

One row per domain with registration and expiry, nameservers, mail records, certificate issuer and the days left before it expires.

$20.00 per 1,000 · Domain reported

The mail side in detail: SPF with its lookup count, DKIM selectors, DMARC policy, MTA-STS and a ranked list of issues.

$3.00 per 1,000 · Domain checked

Five hundred domains cost about $10.00 for the full report, or $2.50 for the mail check alone.