Hostcount is a pan-European research initiative managed by RIPE NCC to provide monthly statistics on the number of hosts connected to the Internet in Europe and the surrounding areas.

RIPE NCC has been running Hostcount, measuring the depth and breadth of the Internet, since 1990. The Hostcount and Hostcount++ tool use the DNS AXFR command to walk the domain name tree to transfer the contents of a whole zone from a nameserver to a client. As the Internet has grown this technique has not scaled adequately. RIPE NCC have now asked several ccTLDs including Nominet, to run part of the replacement tool, Hostcount++. We are pleased to join RIPE NCC's project and hope that our participation will strengthen the quality and value of the data.

What is a host?

For the purposes of Hostcount, a host is a domain name, such as mail.nominet.org.uk. or www.nominet.org.uk, sited at a leaf node of the domain name tree. The Hostcount project attempts to count all the hosts visible on the Internet. In practice, all A records in the Domain Name System (DNS) are eligible to be counted as hosts, but many are discarded, for instance because they have already been seen elsewhere.

What do Hostcount stats tell us?

Ripe publish monthly statistics from Hostcount++ on their web site. These statistics have the potential to:

• Indicate social and economic growth.
• Help us to understand the role the Internet plays in social change.
• Simply show how the distribution of the Internet changes over time.

However, the potential of these statistics depends upon whether or not nameservers block or allow the AXFR command from the Nominet dedicated IP address.

Security issues

Running an AXFR command to transfer the contents of a whole zone from a nameserver can raise security issues. It is usually considered good practice to block AXFR queries from external IP addresses.

Individual DNS records are in the public domain, however the full contents of a zone (or your managed nameserver) have intellectual property rights. To maintain this status, Hostcount++ anonymises all data allowing only volumetric statistical analysis to be undertaken.

Our request

To improve the statistics gathered by Hostcount++ we are asking that all DNS nameservers running zones under .uk to open these zones to AXFR from Nominet's dedicated IP (213.248.199.25).

The statistics generated however are reliant on active participation in the project by registry operators and all nameserver administrators.

Nominet are entrusted with the effective management of the .uk zone and we believe that this project will enable the gathering of statistics that will help the whole global industry develop and move forward.

To find out what you can do to contribute to this research project, please read our technical explanation of Hostcount++ and allowing AXFR.