Is DNSLab free to use?

Yes. Every tool on DNSLab is free with no usage limits for normal interactive use. There's no premium tier that unlocks the real features and no credit card required. The site is supported by unobtrusive ads, which lets us keep the full 50+ tool set open to everyone, from hobbyists checking a personal domain to admins troubleshooting production mail.

Do I need to create an account?

No account, login, or email address is required. Open any tool, run a query, and read the results immediately. Because there's no signup wall, you can bookmark or share a result link and the recipient can view it without registering either. We may add optional accounts later for saved history, but the core tools will stay usable anonymously.

Are the results live or cached?

Results are queried live the moment you submit. DNS lookups hit authoritative name servers, blacklist checks query the DNSBL zones directly, and WHOIS and ASN data come from the responsible registries. This matters because DNS caching and TTLs can hide recent changes — DNSLab shows you the current answer, not what some resolver cached hours ago.

Is my data or query history stored?

The domains and IPs you look up are public technical data, not personal information. Each result is saved so it can be reached again through its shareable link, but queries aren't tied to your identity since there are no accounts. If you'd rather a lookup not be found, simply don't share the link. Standard analytics and ad cookies are covered in our privacy policy.

50+ diagnostic tools

Fast, clean DNS, email & network tools

MX, SPF, DKIM, DMARC, blacklist, DNSSEC, WHOIS and 50+ more — accurate lookups in one clean, modern toolbox.

Shareable result links

Unlike legacy tools, every result is an addressable URL you can bookmark and send.

Instant & live

No stale cache — every lookup is queried live from a worker fleet, so you always see the DNS that is actually published right now.

Secure architecture

An isolated worker fleet runs read-only lookups behind strict SSRF protection on every network probe.

DNS

Resolve any DNS record type.

MX LookupFind the mail servers (MX records) for a domain.A LookupResolve a hostname to its IPv4 address.AAAA LookupResolve a hostname to its IPv6 address.CNAME LookupFind the canonical name a host is aliased to.DNS LookupCheck a domain's authoritative name servers.TXT LookupRead the TXT records published on a domain.SOA LookupRead the Start of Authority record (serial, refresh…).SRV LookupLook up a service (SRV) record.CAA LookupSee which CAs may issue certificates for a domain.Reverse Lookup (PTR)Reverse-resolve an IP address to a hostname.NAPTR LookupbetaNaming Authority Pointer records (ENUM/SIP).TLSA LookupbetaDANE / TLSA certificate association records.

DNSSEC

Signed-zone & DNSSEC records.

DNSKEY LookupPublic keys used to sign a DNSSEC zone.DS LookupDelegation Signer records held by the parent zone.RRSIG LookupbetaDNSSEC resource-record signatures.NSEC LookupbetaNext Secure record (authenticated denial).NSEC3PARAM LookupbetaNSEC3 parameters (hashed denial of existence).CERT LookupbetaCertificate (CERT) records stored in DNS.LOC LookupbetaGeographic LOC records (lat/long/altitude).IPSECKEY LookupbetaIPsec public keys published in DNS.

Email

Deliverability, auth & health.

SPF LookupParse & validate the Sender Policy Framework record.DKIM LookupFetch a DKIM public key for a selector.DMARC LookupParse the DMARC policy at _dmarc.<domain>.BIMI LookupBrand Indicators for Message Identification record.MTA-STS LookupMTA Strict Transport Security TXT record + policy file.TLS-RPT LookupSMTP TLS Reporting (TLSRPT) record.SMTP TestConnect to a mail server, check banner, STARTTLS & open relay.Domain HealthOne-shot report: MX, SPF, DKIM, DMARC, DNSSEC & blacklists.Google / Yahoo ComplianceCheck bulk-sender requirements (SPF, DKIM, DMARC, PTR, TLS).Microsoft ComplianceCheck Outlook.com / Microsoft sender requirements.Email Header AnalyzerPaste raw email headers to trace the delivery path.SPF GeneratorBuild a valid SPF record with a guided form.DMARC GeneratorBuild a DMARC record with a guided form.DMARC Report AnalyzerParse a DMARC aggregate (RUA) XML report.

Reputation

Blacklists & blocklists.

Blacklist CheckCheck an IP or host against ~30 DNS blacklists.Blocklist CheckCheck an IP or host against additional blocklists.

Network

IP, ports, WHOIS, HTTP.

What Is My IPShow your public IP address and its geolocation.WHOIS LookupRegistration details for a domain or IP.ASN LookupLook up an Autonomous System (RDAP).ARIN / IP BlocksWhich network block an IP belongs to (RDAP).PingICMP echo — is the host reachable, and how fast?TraceroutebetaTrace the network path to a host.TCP Port CheckIs a TCP port open on a host? (host:port)HTTP LookupFetch a URL over HTTP and report status, headers & redirects.HTTPS LookupFetch over HTTPS and inspect the TLS certificate.

SSL/TLS

Certificates, CSRs & TLS checks.

SSL CheckerDeep TLS certificate check on any port: chain, expiry, OCSP, HSTS.SSL & CSR DecoderDecode a certificate or CSR in your browser — nothing is uploaded.CSR GeneratorGenerate a CSR and private key in your browser — the key never leaves it.SSL ConverterConvert between PEM, PKCS#12 (PFX) and PKCS#7 — locally in your browser.RSA Key ConverterConvert RSA private keys between PKCS#1 and PKCS#8 in your browser.Certificate Key MatcherCheck that a certificate, CSR and private key match — locally.CA MatcherVerify an end-entity certificate against its CA / intermediate.OCSP CheckerQuery the CA's OCSP responder for live revocation status.CT Log SearchbetaSearch Certificate Transparency logs for a domain's certificates.SSL Handshake TracebetaFull TLS handshake trace to any host and port.Bulk SSL CheckerCheck SSL certificates for a list of hostnames at once.DCV CheckerCheck Sectigo/Comodo domain-control validation (HTTP file & CNAME).

Utilities

Generators & helpers.

Email ExtractorExtract all email addresses from any text.DNS PropagationQuery one record across resolvers worldwide.Subnet CalculatorCIDR → network, broadcast, mask, host range.Password GeneratorGenerate strong random passwords in your browser.LLMs.txt LookupbetaFetch and view a site’s /llms.txt file.Robots.txt AI PolicybetaWhich AI crawlers a site allows or blocks (robots.txt).Bulk LookupbetaRun one tool across a list of domains or IPs.

A complete DNS & email diagnostics toolbox

DNSLab is a free, browser-based toolbox for diagnosing DNS, email deliverability, and network problems. It bundles more than 50 tools — MX, A, TXT and DNSSEC lookups, SPF/DKIM/DMARC validators, blacklist checks, WHOIS and ASN lookups — into one interface, so you don't have to juggle command-line utilities or a dozen scattered websites. Every query runs live against authoritative name servers and public data sources the moment you press enter, not from a stale cache. Each result gets its own permanent URL, so you can hand a failing SPF record or an open resolver to a colleague or hosting provider in one click. There's no signup, no paywall, and nothing to install.

DNS record lookups

Query any record type straight from the authoritative name servers: A, AAAA, MX, CNAME, NS, SOA, TXT, SRV, CAA and PTR. Verify DNSSEC signatures and the chain of trust, check name-server consistency, and catch misconfigurations like missing glue records or mismatched SOA serials before they cause an outage.

Email authentication & deliverability

Diagnose why mail lands in spam or bounces. DNSLab parses and validates your SPF, DKIM and DMARC records, flagging syntax errors, too many DNS lookups in SPF, and weak DMARC policies. It also inspects MX records, reverse DNS (PTR) and SMTP banners so you can confirm receiving servers are reachable and correctly named.

Reputation & blacklist checks

Check an IP address or domain against dozens of major DNSBLs and reputation lists — Spamhaus, SpamCop, Barracuda and more — in a single pass. If a listing is dragging down your delivery, you'll see exactly which lists flagged you and the return codes, so you can request delisting from the right provider.

Network & WHOIS tools

Look up domain and IP WHOIS, registration and expiry dates, ASN ownership and routing prefixes. Run ping, traceroute, port and TCP connectivity tests, plus TLS and certificate checks to trace where a connection breaks. Handy for verifying a migration, tracking down a routing issue, or confirming a certificate chain is complete.

Frequently asked questions

Is DNSLab free to use?: Yes. Every tool on DNSLab is free with no usage limits for normal interactive use. There's no premium tier that unlocks the real features and no credit card required. The site is supported by unobtrusive ads, which lets us keep the full 50+ tool set open to everyone, from hobbyists checking a personal domain to admins troubleshooting production mail.
Do I need to create an account?: No account, login, or email address is required. Open any tool, run a query, and read the results immediately. Because there's no signup wall, you can bookmark or share a result link and the recipient can view it without registering either. We may add optional accounts later for saved history, but the core tools will stay usable anonymously.
Are the results live or cached?: Results are queried live the moment you submit. DNS lookups hit authoritative name servers, blacklist checks query the DNSBL zones directly, and WHOIS and ASN data come from the responsible registries. This matters because DNS caching and TTLs can hide recent changes — DNSLab shows you the current answer, not what some resolver cached hours ago.
Is my data or query history stored?: The domains and IPs you look up are public technical data, not personal information. Each result is saved so it can be reached again through its shareable link, but queries aren't tied to your identity since there are no accounts. If you'd rather a lookup not be found, simply don't share the link. Standard analytics and ad cookies are covered in our privacy policy.