IP

Subnet Calculator

CIDR notation, VLSM breakdown, host counts, and visual subnet maps. Supports IPv4 & IPv6.

networking
DN

DNS Lookup & Propagation

Query A, AAAA, MX, CNAME, TXT, and SOA records. Check propagation across global resolvers.

dns
SS

SSL/TLS Checker

Inspect certificate chains, expiration dates, cipher suites, and HSTS headers for any domain.

security
CR

Cron Expression Builder

Visual cron schedule builder with plain-English translations and next-5-runs preview.

linux
PW

Password & Key Generator

Cryptographically random passwords, SSH keys, and API tokens. Configurable entropy.

security
PT

Port Reference

Searchable database of 6,000+ known ports with service names, protocols, and risk notes.

networking