Codynet

Network tools that just answer the question.

DNS, RDAP, HTTP, TLS, and subnet investigations — deterministic, free, with no query retention.

No accounts. No query retention. Privacy-respecting analytics.

$ query codynet.com MX
status: ok
records:
  priority: 10
  exchange: mail.example.net

$ rdap domain codynet.com
source: HTTPS RDAP
result: structured registration data

Featured tools

Small by design, reusable under the hood.

All tools

DNS Lookup

Resolve common DNS record types with structured output.

Open tool

DIG Lookup

Packet-level DNS queries with raw output, sections, flags, and TTLs.

Open tool

NSLookup

Quick A, AAAA, CNAME, and NS checks in a familiar flow.

Open tool

MX Lookup

Inspect mail exchanger records and priorities.

Open tool

TXT Lookup

Review SPF, DKIM, verification, and other text records.

Open tool

Reverse DNS (PTR)

Resolve an IP back to its hostname via PTR records.

Open tool

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 resolvers

Check a domain's email DNS

Confirm MX routing, then read SPF, DKIM, and DMARC in the TXT records that authenticate mail.

Check email DNS

Check TLS certificate health

Inspect the certificate chain, expiry date, names, and trust before users hit an error.

Inspect a certificate

Audit HTTP security headers

Follow redirects and review HSTS, CSP, and the other response headers that harden a site.

Check headers

Launch or move a domain

Learn which DNS records to set, then verify each one with the matching lookup tool.

Read the guide

Audit many names at once

Run any lookup over a list of domains or IPs and export the results as JSON or CSV.

Run bulk lookups

Guides

Plain-English explanations behind the tools.

All guides

DNS Records Explained

A practical guide to A, AAAA, CNAME, MX, TXT, NS, CAA, and other DNS record types.

Read guide

MX 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 guide

SPF, DKIM, And DMARC Explained

A domain owner's guide to the DNS records that help receivers trust email.

Read guide

SPF 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 guide

TLS Certificate Expiration And Troubleshooting

How to inspect certificate dates, names, issuers, and trust problems before users see errors.

Read guide

NXDOMAIN 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 guide

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.

No query retention

Codynet runs your lookup and does not log or retain the values you search. Your history stays in your browser, and analytics are privacy-respecting.

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.

Built and maintained by Cody Li

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 query content.

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