Enter a domain or an IP address and press Check. The check queries public DNS live and, for official values such as the TTL, the domain’s authoritative servers directly. Each card shows the value found, the technical evidence, what it means and how to fix any problem.
We store the domain checked and the results for 30 days; your IP address is kept only as a salted hash for abuse limits.
What it checks
- Name servers (NS): how many there are, whether they really answer authoritatively and whether they match the delegation at the parent zone (.com, .org, .it…).
- SOA: whether every server holds the same zone version and whether the timers follow the recommendations (RFC 1912, RFC 2308).
- A and AAAA records: IPv4 and IPv6 addresses, with the TTL read from the authoritative server.
- MX: mail servers, Null MX and the most common mistakes (MX pointing to an alias or an IP address, hosts without an address).
- Reverse DNS (PTR) of mail servers and of an IP address, confirmed in the forward direction too.
- CAA: which certificate authorities may issue certificates for the domain.
- DNSSEC: signed or not, complete chain of trust, invalid signatures, deprecated algorithms.
How to read the results
OK means we found no problem. Warning and Error describe a problem, its severity and the steps to fix it. Info flags something that is not an error but worth knowing. Not verifiable appears when a source did not answer or a check cannot be run from our network: we never make up a result.
Limits
Checks run from an Italian connection without IPv6 and without outbound port 25: servers’ IPv6 addresses are reported as “not testable from here”. The tool only reads public data and changes nothing: no DNS, server or mailbox is modified. To prevent abuse there are limits on the number of checks per person and per domain.