Free network tools, no sign-up.

The same checks we run at the start of an engagement, open to anyone. Paste an address and we detect what kind of lookup you need.

Ranges, masks and host counts for IPv4 and IPv6. Runs entirely in your browser — nothing you type is sent anywhere.

The same question asked of eight public resolvers at once, so you can see where a change has propagated and where it has not.

Expiry, issuer, the names it covers, the chain, the protocol and the cipher — and plain sentences about anything that is wrong.

What an address is, what it is for, which registry it was allocated to, and what it calls itself in reverse DNS.