Network diagnostics

Traceroute shows the hops between you and a host. How to read a traceroute walks through that output. DNS lookup returns the records for a name. Reverse DNS returns the hostname for an address. WHOIS and ASN lookup show who registered a domain or which network announces a prefix. The port scanner checks common TCP ports.

The IP lookup page shows location, ASN, ISP, reverse DNS, and a blacklist count for one address. The subnet calculator shows the mask, wildcard, host range, and host count for a prefix as you type. The CIDR calculator converts a prefix to a range and an IPv4 range back to the smallest CIDR blocks.

The other groups are leak tests, IP lookup and geolocation, and email and domain security.