Diagnose DNS, authentication, mail servers and reputation. Each check explains what it found and exactly how to fix it.
Full technical diagnosis of an email address: mailbox, domain, DNS, SMTP, authentication and blacklists.
Paste email headers to see the delivery path, delays and SPF / DKIM / DMARC results.
Paste a bounce or SMTP error and get a plain-language explanation and fix.
Complete email health report for a domain: DNS, MX, SPF, DKIM, DMARC, MTA-STS, blacklists.
Mail server records, IPs, reverse DNS and connectivity.
Validate SPF, count DNS lookups and view the full include tree.
Look up a DKIM selector or discover common selectors, and inspect the key.
Validate the DMARC policy, reporting addresses and alignment settings.
Reverse DNS and forward-confirmed reverse DNS for an IP address.
Connect to a mail server on ports 25 / 465 / 587: banner, EHLO, STARTTLS, certificate, timings.
Check an IP or domain against many DNS blocklists at once.
Blacklists, reverse DNS, authentication and third-party reputation indicators in one view.
Build a valid SPF record from the services you use, with a DNS lookup count.
Create a DMARC policy with reporting addresses and alignment settings.
