Try the new IANA WHOIS server

by Kim Davies on May 20, 2010

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.

{ 6 comments… read them below or add one }

Anne 06.04.10 at 12:14 pm

While trying to retrieve the URL:

The following error was encountered:

Unable to determine IP address from host name for unknown server name

Kim Davies 06.04.10 at 1:22 pm

The WHOIS server is at not

Robert Martin-Legene 06.22.10 at 12:59 am

I don’t see the “refer:” but only “whois:”. How do I get the magic refer: attribute?

Kim Davies 06.22.10 at 2:25 am

refer: attribute is only shown if it a query for a subdomain of the TLD, or a more specific IP address than the record IANA keeps. i.e. “” will produce a refer field. “dk” will not refer as we are authoritative for the most specific answer.

Robert Martin-Legene 08.29.10 at 11:12 pm

The refer: works. I think this is an excellent solution (to only show the refer when it’s for a subdomain).

Another point I wanted to raise: When I query the whois the “purpose” isn’t shown. I don’t know if it was ever shown on the whois-server but “I miss it”. Your webpage has that information. Any chance of getting that information in there? Should I mail someone instead of writing on a random blog?

Kim Davies 08.30.10 at 8:11 am

The WHOIS service only provides a subset of data on the website. It hasn’t lost any information from the previous version, but we’ll consider feature requests if it is useful for specific information to be added.

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