Network

Convert any MAC address into its modified EUI-64 interface ID and the matching IPv6 link-local address — the same form Windows / Linux compute automatically.

Build URLs by combining a base address with editable key-value query parameters — each pair toggleable, properly percent-encoded.

Type an IPv4 or IPv6 address and see its class, scope (private / public / loopback / link-local), decimal value, binary, reverse-DNS notation, and /32 CIDR.

Searchable cheat sheet for ~60 standard TCP / UDP port numbers — from 22 (SSH) and 80 (HTTP) to 6379 (Redis) and 27017 (MongoDB).

Searchable cheat sheet for DNS record types — A, AAAA, CNAME, MX, TXT, NS, SOA, PTR, SRV, CAA, DNSSEC, SVCB / HTTPS — with examples.

Parse an IPv4 CIDR into network address, broadcast, netmask, wildcard, host range, and class. Shows binary breakdown and private/public status.

Parse a User-Agent string into browser, engine, OS, device, and CPU. Detects 20+ bots including GPTBot, ClaudeBot, PerplexityBot.

Toggle any IPv6 address between its shorthand ::1 form and the fully-expanded 8-group representation, with reverse DNS and binary too.

Paste a raw email header to walk the Received hops in order, see the per-hop delay, and read off the SPF/DKIM/DMARC verdicts.

Build an HTTP Cache-Control header from a visual checklist — freshness, revalidation, immutability, and the common presets.

Build a CSP header from per-directive source lists, with three starter presets and live warnings for the dangerous wildcards.