Skip to main content

Try the new IANA WHOIS server

We currently provide a WHOIS server at which provides the ability to lookup information for a certain subset of domains, most notably the details of top-level domains. One of the projects we’ve been working on within the IANA department is to develop a new WHOIS server to cope with increased use cases, and generally perform the function in a better way.

Today, we are pleased to provide a test version of the new WHOIS server for you to experiment with and provide feedback on. It is online at Here is a sample:

Here are some of the things worth noting with this WHOIS server:

  • New format. The first thing that one would notice comparing the output is that we have adopted a new RPSL-style output format. It is a more predictable format that is commonly used by other WHOIS services, and also is easier to parse with a predictable “key: value” format.
  • IDN support. We’ve improved the IDN support in this WHOIS server, so that we accept both the ASCII-based wire-format (i.e. prefixed with xn--) and the Unicode presentation format (encoded in UTF-8) as arguments to the WHOIS server. For IDNs, we return both formats in the result, with the U-label under the domain: key, and the A-label under the domain-ace: key.
  • IP addresses. One of the great new features is IP address support. We maintain the global address space for both IPv4 and IPv6 and maintains the authoritative top-level delegation of address blocks. You can now query for any IP address and either get the top-level allocation (e.g. to a Regional Internet Registry), or its reserved status. This works for AS numbers too.
  • Referrals. When a domain name or an IP address block is delegated to a more specific registry (i.e. either a top-level domain registry, or an RIR), and we have information on a WHOIS server that has more specific information, we’ll first return a refer: key and the WHOIS server with the more specific information. This effectively allows you to query IANA’s WHOIS service for any domain, IP address or AS number to determine the best place to look.

So, give it a try and let us know what you think. We only ask that you please not hardcode the host into anything as this is temporary while we experiment. Ultimately the WHOIS server is anticipated to replace what is used today. Incidentally the existing WHOIS server is one of the oldest pieces of code still in service in ICANN so retiring it will be a pleasure for all concerned.


    Domain Name System
    Internationalized Domain Name ,IDN,"IDNs are domain names that include characters used in the local representation of languages that are not written with the twenty-six letters of the basic Latin alphabet ""a-z"". An IDN can contain Latin letters with diacritical marks, as required by many European languages, or may consist of characters from non-Latin scripts such as Arabic or Chinese. Many languages also use other types of digits than the European ""0-9"". The basic Latin alphabet together with the European-Arabic digits are, for the purpose of domain names, termed ""ASCII characters"" (ASCII = American Standard Code for Information Interchange). These are also included in the broader range of ""Unicode characters"" that provides the basis for IDNs. The ""hostname rule"" requires that all domain names of the type under consideration here are stored in the DNS using only the ASCII characters listed above, with the one further addition of the hyphen ""-"". The Unicode form of an IDN therefore requires special encoding before it is entered into the DNS. The following terminology is used when distinguishing between these forms: A domain name consists of a series of ""labels"" (separated by ""dots""). The ASCII form of an IDN label is termed an ""A-label"". All operations defined in the DNS protocol use A-labels exclusively. The Unicode form, which a user expects to be displayed, is termed a ""U-label"". The difference may be illustrated with the Hindi word for ""test"" — परीका — appearing here as a U-label would (in the Devanagari script). A special form of ""ASCII compatible encoding"" (abbreviated ACE) is applied to this to produce the corresponding A-label: xn--11b5bs1di. A domain name that only includes ASCII letters, digits, and hyphens is termed an ""LDH label"". Although the definitions of A-labels and LDH-labels overlap, a name consisting exclusively of LDH labels, such as"""" is not an IDN."