Network tools
Quick checks for DNS, mail, TLS and HTTP configuration. Each tool is also available through the API.
Network
Geofeed checkerValidate an RFC 8805 geofeed
IPv6 readiness testDoes your connection work over IPv6?
Prefix toolsMerge prefixes, ranges to CIDR, IPv6, reverse zones
DNS blocklist checkCheck an IPv4 address on 18 blocklists
Subnet calculatorIPv4 and IPv6 ranges and masks
DNS and mail
DNS record lookupA, AAAA, MX, TXT, NS, CAA, SOA and more
DNS propagation checkSee a record on 21 resolvers worldwide
Email header analyzerHops, delays, SPF, DKIM and DMARC
DNS leak testWhich DNS servers does your browser use?
Mail configuration checkMX, SPF and DMARC in one check
Web
TLS certificate checkIssuer, validity and SAN names
HTTP header checkServer, caching and security headers