Networking Tools

Parse and validate IPv4/IPv6 addresses and CIDR ranges

Quick lookup of HTTP status codes and their meanings

Explain A, AAAA, CNAME, MX, TXT, SRV and other DNS records

Decode WebSocket frame headers and payloads from hex

Look up common services for any TCP/UDP port number

Convert between file extensions and MIME types

Decode X.509 PEM certificates into readable fields

Generate HTTP Public Key Pinning headers from a certificate

Parse browser, OS, device from a User-Agent string

Analyze CORS response headers for misconfigurations and security issues

Calculate network address, broadcast, host range from CIDR notation

Analyze HTTP headers for security, caching, and best practices

Identify the manufacturer from a MAC address OUI prefix

Quick reference for all HTTP methods with use cases and safety info

Build ?k=v&k=v strings from key=value lines — repeating keys OK

Base64-encode user:pass into an HTTP Basic Authorization header

Wrap a raw token in HTTP Authorization + curl + fetch snippets

Compose request headers — output as curl flags and fetch options

CIDR → subnet mask, network, broadcast, first/last host, host count

Expand ::abbreviated IPv6 and also emit the canonical compressed form

IPv4-mapped IPv6 address (::ffff:a.b.c.d) — RFC 4291 representation

Search 25+ foundational RFCs by number, title, or topic

40+ standard TCP/UDP ports — search by number, service, or keyword

Build dig/nslookup/resolvectl commands for a domain and decode the answer section you paste back (no lookup is performed)

Build whois/RDAP commands and decode a pasted WHOIS response — dates, EPP status codes, nameservers and redactions (no registry is queried)

Classify an IP offline, learn what GeoIP can and cannot tell you, and get the commands to query a real GeoIP source

CIDR subnet calculator with utilities

Build nmap/nc/PowerShell scan commands for a host and port range, and annotate scanner output you paste back (nothing is scanned here)