Tools for network admins and ISPs — calculators, DNS diagnostics, WHOIS, and more.
Network & DNS
IPv4 Subnet Calculator
Calculate the network address, broadcast, mask, and host range for a given CIDR.
IPv6 Subnet Calculator
Compress or expand an IPv6 address to its canonical form and calculate the network address, last address, and address count for a given prefix — entirely in your browser.
DNS Lookup
Check A, AAAA, MX, TXT, or NS records for any domain.
WHOIS
Check registration data for a domain or IP address — registrar/RIR, dates, ASN, CIDR range.
Reverse DNS / PTR
Check the PTR record (hostname) for an IPv4 or IPv6 address.
My IP
Check your IPv4 and IPv6 address at once — with ASN, network operator, country, and rDNS for each.
DNS Propagation
Compare a DNS query's result across several public resolvers.
Looking Glass
Check ping, traceroute, and BGP entries from the perspective of the public TPIX and RETN looking glasses.
IP / ASN WHOIS
Block or ASN holder, RIR, status, announced prefixes and approximate geolocation — for an IP address, prefix or AS number. Data: RIPEstat.
RPKI / ROA Checker
Check whether a prefix announced by a given ASN matches its ROAs (RPKI) — valid, invalid or no ROA. Data: RIPEstat.
IP Abuse Contact Lookup
Find the abuse e-mail address for an IP address or prefix, together with its source in the RIR database. Data: RIPEstat.
MAC Vendor Lookup
Look up a network card's vendor from its MAC address (IEEE OUI registry) — single or batch lookup, entirely in your browser.
Security & Cryptography
SSL/TLS + Security Headers
Check the SSL/TLS certificate and security headers of any domain.
Email Deliverability Checker
Check SPF, DKIM, and DMARC — the configuration that determines whether your emails get delivered.
SSH Key Generator
Generate an SSH key pair (Ed25519 or RSA) — entirely in your browser, with no data sent to a server.
SSH Fingerprint Converter
Compute the SHA256 and MD5 fingerprint of an SSH public key — entirely in your browser.
Password Generator
Generate a strong, random password with a configurable character set — entirely in your browser.
Hash Generator
Compute the MD5, SHA-1, SHA-256, SHA-512, or Bcrypt hash of any text — entirely in your browser.
Let's Encrypt Certificates
Issue a Let's Encrypt certificate (including wildcard) via the DNS-01 method, with no server access needed — just your DNS provider's control panel.
JWT Decoder
Decode a JWT's header and payload (Base64URL -> JSON) — entirely in your browser, without signature verification.
Base64 / URL / Hex Encoder/Decoder
Encode or decode text as Base64, URL (percent-encoding), and Hex, with full UTF-8 support — entirely in your browser.
Configuration & Automation
Device Configuration Generator
Generate a baseline router (WAN/LAN/NAT/firewall) or switch (VLAN/ports/management) configuration for MikroTik, Cisco, pfSense, or DCN.
Cron Expression Editor
Build or paste a cron expression — get a human-readable description and a preview of the next run times, entirely in your browser.