Domain Survey Definitions

These are definitions of terms used by the Internet Domain Survey. Not everyone uses these terms with the same meanings.
domain name
A domain name is any name representing any record that exists within the Domain Name System. ie. com,,
A domain is a domain name that has name server (NS) records associated with it. In other words, there may be subdomains or hosts under it. ie. com,
domain server
A domain server is a system that hold all the records associated with a particular domain, and answers queries about those names.
domains queried/domains missed
Domains queried refers to how many domains we could query by connecting to the domain server and asking it for a dump of the domain. Domains missed is the number of domains that we could not query, because we couldn't connect to the appropriate server or the server refused the query.
domain (top-level)
A top-level domain name is either an ISO country code or one of the generic domains (com/org/net/etc). It should be noted that there is not necessarily any correlation between a country code and where a host is actually located.
A host is a domain name that has an IP address (A) record associated with it. This would be any computer system connected to the Internet (via full or part-time, direct or dialup connections). ie.,
host name (or firstname)
A host name is the first part (before the first dot) of a hosts' domain name. ie. www
network numbers (class a/b/c)
A network number is the first part of an IP address that identifies what network the hosts numbered in the rest of the address are connected to. The Class A/B/C system is no longer used and the data is presented only for historical reasons. It is no longer possible to tell how many network numbers are in use by looking at IP addresses, since the netmask can not be determined from the number. Also, note that domains do not map directly to particular network numbers and no correlation between them can be inferred.
zone transfer
A zone transfer is the process of downloading all the records associated with part of a domain from a domain server.