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Internet Statistics

RIPE Region Hostcount++: Label Explanation

AXFR Block - Hosts or Counted - Duplicate - Empty - Huge - Large - Level - Medium - No Response Zones - People / Host - Population - Real or Real Hosts - Small - TLD - WWW Sites - Zones - Visibility - IPv4 / IPv6

AXFR Block

A common reason for host failing to transfer a zone is that one or all of the nameservers for the zone refuse the zone transfer query.

Since the accuracy of the hostcount++ is completely dependent on being able to do as many zone transfers as possible, we track how frequently this occurs.

Beware! This figure is not the number of zone transfers which were blocked during the course of the hostcount++! It's the number of zones for which enabling zone transfers on one of the servers would have meant we could have transferred the zone.

Examples. Suppose zone x.y.z is listed as being served by nameservers A and B, then...

  • if a zone transfer from A is successful, then we don't care what B says, so x.y.z is not counted as AXFR blocked.
  • if a zone transfer from A fails because A is a lame delegation then x.y.z is not counted as AXFR blocked.
  • if a zone transfer from A fails, and a zone transfer from B fails because B is a lame delegation, then x.y.z is counted as AXFR blocked.
  • if zone transfers from A and B both fail, then x.y.z is counted as AXFR blocked, but only once.

Counted

The number of hosts which were counted while traversing the DNS.

Duplicate

The number of hosts which were seen while traversing the DNS which had already been seen elsewhere.

This only applies within a particular TLD.

Empty / Small / Medium / Large / Huge

These labels refer to a classification decided by the size of a zone, where 'size' is determined by the number of hosts found in the zone. The following table shows the cut-off points for the 5 classifications...
Classification Hosts in Zone
Empty 0
Small 1-10
Medium 11-100
Large 101-1000
Huge 1001+
Some examples... a figure like empty | zones | 50, indicates that there were 50 zones found which contained no hosts. A combination like large | hosts | 2900 indicates that 2900 hosts on average were found in zones with 101-1000 hosts.

Level X

The level in the Domain Name tree which is being analysed. For instance, data from Level 1 refers to one or more TLDs (depending on where it appears).

The hostcount++ software analyses all levels which exist in the data. However, to make results more presentable the numbers for all zones greater than level five are merged with the totals for level 5, hence the label Level 5+.

No Response Zones

The number of zones which could not be transferred and analysed by host.

The particular reasons why host can fail to transfer a zone vary. Common reasons are:

  • connectivity problems, such as timeouts
  • zone transfer restrictions by a nameserver for the zone
  • lame delegation of the zone to a nameserver (i.e. a nameserver listed as being authoritative for the zone does not seem to know anything about the zone, or does not think it is authoritative).

People / Host

The number of people per real host for a given TLD.

Population

The estimated number of people living in the country represented by this TLD, where applicable.

The data is extracted from the CIA world factbook and is revised each year.

Not all TLDs will have a corresponding population figure. Possible reasons are

  • no figures are available
    e.g. gg (Guernsey).
  • the geographic area corresponding to the TLD no longer exists
    e.g. su (Soviet Union).
  • the TLDs population is covered by another TLD
    e.g. gb (Great Britain) is covered by uk (United Kingdom), gg is possibly covered by uk.

Real or Real Hosts

The number of non-duplicate hosts. This is always obtained by subtracting the duplicate hosts from the hosts that were counted.

TLD

TLD stands for Top Level Domain. The DNS tree is made up of several generic TLDs like .com and lots of so-called country code Top Level Domains (ccTLD), which in general correspond to existing states or geographic areas in the real world. ccTLDs are all designated by two letters and correspond, with a very few exceptions, to the two-letter country codes of the ISO 3166 standard.

In the context of this hostcount++, TLD refers to the ccTLDs in the RIPE NCC service area.

WWW Sites

This refers to address records counted of which the first label in their domain name was www e.g. www.xxx.nl. The vast majority of WWW sites have a domain name of this format, so this is a fairly good indication of the number of web sites within a particular TLD.

Duplicates domain names are removed.
Two different names with the same address are counted as two WWW sites.

Zones

The total number of zones which were analysed, either at a particular level of the Domain Name tree, of a particular size, for a particular TLD or over all of the TLD's in the hostcount++.

Note that zones which were encountered in an NS record but which could not be retrieved via the DNS, for whatever reason, are not included.

Visibility

The percentage of visible hosts among the whole amount.

Whether a host is visible or not is decided on the basis of the following logic:

  • For IPv4:

    If a RIS WHOIS DB response for a /24 subnet, including the host contains at least one route object less or equal /8, then the subnet and the host is considered visible.

  • For IPv6:

    If a RIS WHOIS DB response for a /24 subnet, including the host contains at least one route6 object, then the subnet is visible.

IPv4 / IPv6

Hostcount++ counts hosts with both IPv4 and IPv6 addresses, contrary to Hostcount which counts only hosts with IPv4 addresses. In some tables a distinction between IPv4 and IPv6 is made. In the places where the type of address is not explicitly mentioned, a total of IPv4 and IPv6 is used.