DNS Pro
DNS Pro is a growing collection of DNS lookup, email policy, domain intelligence, DNS auditing, and practical infrastructure tools for troubleshooting, migration checks, and security reviews.
Discovery
Record Lookups
Record Lookup
Query A, AAAA, CNAME, NS, PTR, SOA, SRV, CAA, and TXT records.
NS Lookup
Check authoritative nameserver records directly.
MX Lookup
Check mail exchange records, priorities, and resolved IPs.
TXT Lookup
Check TXT records, TTL values, and full text content.
CAA Analysis
Review certificate authority authorization records and tags.
PTR Check
Validate reverse DNS and forward-confirmed PTR results.
Email & Security
SPF Checker
Break down SPF mechanisms, redirects, includes, and lookup count.
SPF Flattener
Generate a flattened SPF-style output from the current effective SPF policy.
DMARC Checker
Inspect DMARC policy, reporting, and alignment tags.
DKIM Checker
Check DKIM records with a selector.
Email Security Check
Review SPF, DMARC, DKIM, MTA-STS, TLS-RPT, and BIMI together.
MTA-STS Check
Check the MTA-STS TXT record and HTTPS policy file.
TLS-RPT Check
Inspect TLS-RPT reporting records.
BIMI Check
Inspect BIMI TXT records and parsed BIMI tags.
Blacklist Checker
Check whether a domain or IP appears on common blocklists.
Email Header Analysis
Analyze email headers for SPF, DKIM, DMARC, and routing clues.
Domain Intelligence
DNS Audit
Run a broad DNS and email configuration audit.
Domain DNS Summary
See a broad one-page view of key DNS records for a domain.
Whois Lookup
Inspect domain registration, registrar, and nameserver information.
DNSSEC Checker
Check whether DNSKEY and DS records are present.
DNS Propagation Checker
Compare answers across public resolvers.
Glue Record Checker
Inspect in-bailiwick nameservers and glue-related addressing.
Networking Tools
Learning Articles
CIDR cheat sheet (common subnet sizes)
Quick reference for common CIDR ranges, subnet masks, block sizes, and usable host counts for fast subnet calculations.
How to calculate a subnet range
A practical guide to calculating network address, broadcast address, and usable host range from an IP address and subnet size.
What is a subnet mask?
Learn what a subnet mask does, how it defines network boundaries, and how it relates to CIDR notation and usable host ranges.
What is CIDR notation?
Learn what CIDR notation means, how /24 or /27 prefixes work, and how CIDR relates to subnet masks and IP ranges.
Common Glue Record Problems: DNS Delegation Issues Explained
A complete troubleshooting guide to glue record issues, including in-bailiwick nameservers, missing glue, delegation mismatches, and how to fix DNS resolution failures.
Common PTR Record Problems: Reverse DNS Issues Explained
A complete guide to PTR record problems, including missing reverse DNS, forward-confirmed reverse DNS (FCrDNS), hostname issues, and how PTR impacts email deliverability.
DMARC record explained
A practical breakdown of a DMARC record, including what each tag means and how to interpret the policy.
DNS Records Required for Google Workspace (Complete Setup Guide)
Complete guide to Google Workspace DNS records including MX, SPF, DKIM, DMARC, and domain verification. Includes real record examples and setup best practices.
What DNS Pro is for
DNS Pro is designed to make DNS lookups, domain intelligence, email-related troubleshooting, and related network calculations easier to understand. The goal is to present technical data in a practical way, with context and useful export options.