NetToolset

Choose a calculation or reference for address planning, or a lookup for current public data. NetToolset maps CIDR input to network, broadcast, mask and host range, and includes download-time arithmetic, speed-unit conversion and protocol references. Its DNS lookup takes a domain and record type. The site describes the tools as free with no signup. It says calculations that can run in the browser do so, while DNS and IP-geolocation lookups contact public endpoints such as Cloudflare and ipify directly from the browser. Treat those as different processing paths; an arithmetic result describes the supplied values, while a DNS answer reflects the queried resolver.