NetQuery supports natural-language requests, direct domains or IP addresses, and focused command:value lookups. Use explicit commands when you already know the diagnostic you want; use natural language when you want NetQuery to route the investigation.
mx:example.com
Use MX diagnostics to identify the mail exchangers responsible for a domain and verify that priorities and hosts match the intended mail provider.
dmarc:example.com
Use DMARC diagnostics to inspect policy and reporting configuration, then correlate the result with SPF and DKIM alignment.
tls:example.com
Inspect the certificate and TLS configuration exposed by a public endpoint.
Open the SSL/TLS certificate and cipher check
smtp:mail.example.com
Check public SMTP reachability and advertised capabilities such as STARTTLS.
Check the mail configuration for example.com
Does example.com have DMARC configured?
Check TLS for mail.example.com
Audit example.com's email security posture
Why might mail from example.com fail authentication?
mx:example.com
smtp:mail.example.com
Then validate SPF, DKIM, DMARC, TLS and reverse DNS as the evidence requires. See email delivery troubleshooting.
Start with the chain-of-trust view rather than inspecting a single record in isolation.
Use the CIDR calculator for range boundaries, then pivot into ASN ownership, PTR and FCrDNS.
The full NetQuery tool library is available at https://netquery.tools.