Codynet
Network tools that just answer the question.
DNS, RDAP, HTTP, TLS, and subnet investigations — deterministic, free, with transparent privacy limits.
No accounts. No tracking cookies. Limited operational analytics.
$ query codynet.com MX
status: ok
records:
priority: 10
exchange: mail.example.net
$ rdap domain codynet.com
source: HTTPS RDAP
result: structured registration dataFeatured tools
Small by design, reusable under the hood.
DNS Lookup
Resolve common DNS record types with structured output.
Open toolDIG Lookup
Packet-level DNS queries with raw output, sections, flags, and TTLs.
Open toolNSLookup
Quick A, AAAA, CNAME, and NS checks in a familiar flow.
Open toolMX Lookup
Inspect mail exchanger records and priorities.
Open toolTXT Lookup
Review SPF, DKIM, verification, and other text records.
Open toolReverse DNS (PTR)
Resolve an IP back to its hostname via PTR records.
Open toolPopular lookups: online nslookup tool, MX record lookup, online dig tool, TXT record lookup, reverse DNS (PTR) lookup, and DNS lookup.
Start with a workflow
Not sure which tool you need? Start from the job you're doing.
Debug DNS propagation
Run the same record across Cloudflare, Google, and Quad9 to see who has the new answer yet.
Compare resolversCheck a domain's email DNS
Confirm MX routing, then read SPF, DKIM, and DMARC in the TXT records that authenticate mail.
Check email DNSCheck TLS certificate health
Inspect the certificate chain, expiry date, names, and trust before users hit an error.
Inspect a certificateAudit HTTP security headers
Follow redirects and review HSTS, CSP, and the other response headers that harden a site.
Check headersLaunch or move a domain
Learn which DNS records to set, then verify each one with the matching lookup tool.
Read the guideAudit many names at once
Run any lookup over a list of domains or IPs and export the results as JSON or CSV.
Run bulk lookupsGuides
Plain-English explanations behind the tools.
DNS Records Explained
A practical guide to A, AAAA, CNAME, MX, TXT, NS, CAA, and other DNS record types.
Read guideMX Records And Email Routing
How mail exchanger (MX) records control email routing for a domain, and how to troubleshoot MX routing when mail delivery breaks.
Read guideSPF, DKIM, And DMARC Explained
A domain owner's guide to the DNS records that help receivers trust email.
Read guideSPF Record Failing? How To Read It In DNS
How to find your SPF record in DNS, read every mechanism and qualifier, and fix the real failures: softfail to spam, the 10-lookup permerror, and duplicate records.
Read guideTLS Certificate Expiration And Troubleshooting
How to inspect certificate dates, names, issuers, and trust problems before users see errors.
Read guideNXDOMAIN vs SERVFAIL: What DNS Errors Actually Mean
What is NXDOMAIN and what is SERVFAIL? NXDOMAIN means the DNS name does not exist; SERVFAIL means the resolver could not get a clean answer. Two different DNS errors, two different fixes.
Read guideLatest notes
What I am learning, changing, and fixing as I maintain Codynet.
I Found Out Why an HTTP Header Check Took 16 Seconds and Fixed It
One unusual hostname made the HTTP Header Tool wait twice as long as necessary and return a confusing error. I traced the problem, removed the unnecessary retry, and made the result clearer.
What Changed on Codynet — June 2026
A short, honest log of what we deepened across the tools and guides this month, and the principle behind every change: show the protocol's real answer.
Why Two DNS Resolvers Give You Different Answers
Cloudflare says one thing, Google says another, and your laptop says a third. A field note on why that happens, when it is normal, and when it means something is actually broken.
Why Codynet is different
Built to answer one question fast, then get out of your way.
Deterministic answers
Lookups run against real DNS resolvers and HTTPS RDAP endpoints, and show you the raw, structured response — not a guess or a cached marketing page.
Limited operational analytics
Your History drawer stays in your browser. Codynet retains limited normalized query and request metadata for 90 days, not full result payloads.
Tools that connect
Results link straight into the next tool — an IP to its reverse DNS and owner, a host to its DNS and TLS — so an investigation flows without retyping.
Free and account-free
No sign-up, no paywall, no project setup. Open a tool, run the lookup, and copy or export what you need.
Independently built and maintained
Codynet is an independent network utility project built to make DNS, RDAP, TLS, HTTP-header, and subnet troubleshooting easier to verify. The tools show structured protocol results, explain common findings, and do not retain full result payloads.
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