Free IT & network tools for sysadmins and developers

DNS

DNS Lookup ★︎

Query any DNS record type for a hostname (A, MX, TXT, CAA…).

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DNS

Bulk DNS Lookup ★︎

Check many domains at once and export the results to CSV.

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SSL & certificates

Let's Encrypt Wizard ★︎

Issue a free Let's Encrypt SSL certificate manually — HTTP or DNS validation.

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SSL & certificates

SSL Checker ★︎

Validity, chain, expiry and hostname match for any server.

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SSL & certificates

PEM to PFX ★︎

Bundle a certificate, key and chain into a password-protected .pfx.

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SSL & certificates

CSR Generator ★︎

Generate a private key and a CSR with SANs, RSA or ECDSA.

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SSL & certificates

CSR Decoder ★︎

Decode a CSR and verify its self-signature.

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SSL & certificates

CRT Decoder ★︎

Read subject, issuer, SANs, fingerprints and expiry from a certificate.

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SSL & certificates

Key & CRT Match ★︎

Check that a private key really belongs to a certificate.

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SSL & certificates

Certificate Transparency Search ★︎

Every certificate ever issued for a domain — and the subdomains they reveal.

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Server

htpasswd Generator ★︎

Create a .htpasswd user line (bcrypt, APR1 or SHA) to protect a folder.

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SSL & certificates

TLS Protocol Scan ★︎

Which TLS versions a server accepts, plus the cipher it negotiates.

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SSL & certificates

PFX to PEM ★︎

Split a .pfx / .p12 back into its certificate, key and chain.

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Network

Whois ★︎

Registrar, status, dates and nameservers for a domain or IP.

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Network

Blacklist Check ★︎

Is your mail server IP on a spam blacklist? Checks 51 public DNSBLs.

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Network

IP Info ★︎

Geolocation, ASN, ISP and reverse DNS for an IP or hostname.

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Encoding

Base64 Encode / Decode ★︎

Encode or decode Base64 text, in the browser.

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Developer

HTML Sandbox ★︎

Write HTML, CSS and JS and see it render live, isolated from the site.

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Developer

I or L Checker ★︎

Tell l, I, 1, O and 0 apart — and catch invisible or fake Unicode characters.

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Encoding

URL Encode / Decode ★︎

Percent-encode or decode URLs and query strings.

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