Compute network boundaries, first/last usable host IPs, and Cisco wildcard masks.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Type an IPv4 network address with prefix length (e.g. 192.168.1.0/24).
Inspect usable host range (First IP – Last IP), total address capacity, and broadcast address.
Copy the complete subnet specification to configure routers or firewall security groups.
A wildcard mask is the inverse of a subnet mask (e.g., netmask 255.255.255.0 has wildcard 0.0.0.255), used in Cisco ACLs and OSPF routing configurations.
The first address is reserved as the Network ID and the last address is reserved as the Subnet Broadcast IP.
Zero-egress companion tools in the Security & Network suite
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Audit CSP, HSTS, X-Frame-Options, and security headers with OWASP grading (A+ to F).
Compare memory hardness, GPU ASIC resistance, and security parameters across KDF standards.
