subnetz.dev
Free tools for IT and network admins.
Subnet Calculator
IPv4 and IPv6 subnetting: network, broadcast, host ranges and CIDR splitting.
SSL Checker
Inspect a server's certificate chain, expiry, SANs and TLS configuration.
CSR Generator
Generate certificate signing requests and private keys locally in your browser.
MX & Mail Routing
Check MX records, SPF, DKIM and DMARC for a domain.
What's My IP
Your public IP address with geolocation and network details.
VPN Checker
Detect whether your connection goes through a VPN, proxy or Tor exit node.
DNS Propagation
Query DNS records across public resolvers to track propagation.