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Look up a domain's SOA record

The SOA record describes a domain's DNS zone. Enter the domain to see its primary server and serial number.

What does the SOA record contain?

The SOA (Start of Authority) is the first record of every DNS zone. Its values, in the order they appear, are:

  • The zone's primary DNS server.
  • The administrator's email, with the first dot in place of the at sign.
  • The serial number, which goes up with every change (often in date format: 2026103001).
  • Refresh, retry and expire: how often secondary servers check for changes, how long they wait if that fails and when they stop answering.
  • The negative TTL: how long the “does not exist” answer is cached.

Lookups by record type

A recordsThe IPv4 address a domain points to.AAAA recordsThe IPv6 address a domain points to.CNAME recordsAliases that point to another name.MX recordsThe servers that receive the domain's email.NS recordsThe domain's authoritative DNS servers.TXT recordsSPF, DKIM, DMARC and domain verifications.SOA recordZone data: primary server, serial and timers.CAA recordsWhich authorities may issue SSL certificates.

Frequently asked questions

What is the serial number for?

Secondary servers compare it with their own: if the primary's is higher, they download the updated zone. If you edit the zone by hand and do not increase it, the changes are not replicated.

How long does a DNS change take to propagate?

As long as the old record's TTL: from a few minutes to 24 or 48 hours. Nameserver (NS) changes usually take longer, because the TTL of the delegation in the TLD is high.

What does NXDOMAIN mean?

That the name you looked up does not exist in DNS: the domain is not registered, has expired or was mistyped.

Which DNS servers does this tool ask?

No middleman: Netlupa runs its own resolver, which starts from the root servers and asks each domain's official DNS servers directly.

Can I do a reverse DNS lookup of an IP?

Yes: look the IP up with the API (/api/dns/ptr/8.8.8.8) or use the WHOIS tool to find out who it belongs to.

Why do I see a different value than in my DNS panel?

Because resolvers still have the previous value cached. Wait for the time shown in the TTL, or check that you edited the zone at the provider listed in the NS records: if the domain uses other DNS servers, changes in your panel have no effect.

What is a record's TTL?

The time, in seconds, other servers may keep the answer before asking again. 3600 is one hour. A low TTL makes changes show up sooner, at the cost of more queries.

Try another tool

Domain and IP WHOISRegistrar, dates, nameservers and owner of a domain or an IP.SPF, DKIM and DMARC checkerCheck whether a domain's email is properly authenticated and why it may land in spam.IP lookupCountry, city, provider and coordinates of any public IP.