Technical data

the network. BIND can also provide information on available mail servers and
well-known services for a domain.
Based on a client/server model, BIND servers maintain databases of host names,
IP addresses, mail records, text records, and other network objects. When client
systems require this information, they query the servers.
IP address space allocation is one of the many duties for which ICANN (Internet
Corporation for Assigned Names and Numbers), a non-profit corporation, assumes
responsibility. ICANN also manages protocol parameter assignment, domain name
system management, and root server system management functions, which were
previously performed under U.S. Government.
8.2 BIND Service Components
The BIND service contains two parts: the BIND resolver and the BIND server.
• BIND resolver — client software interface that:
– Formulates queries.
– Sends queries to BIND servers for answers.
– Interprets the server’s answer.
– Returns the information to the requesting network application.
• BIND server — server software that responds to client queries by providing:
– Authoritative or nonauthoritative answers to queries about host names and
IP addresses for which the server has an answer.
– Information about other authoritative servers that can answer queries
about host names/IP addresses for which the server does not have an
answer.
– Information about how to get closer to the answer if the server does not
have either an answer or information about other authoritative servers
– Information about mail servers and other network application servers (for
example, FTP, TELNET).
8.3 Domains
The Internet name space is based on a hierarchical tree structure. Each node in the
tree is referred to as a domain or a subdomain. A domain is an administrative
entity that allows for decentralized management of host names, addresses, and
user information. Domains can refer to an administrative point in the name space
tree or a specific host. A domain is identified by a domain name and includes
the name space at or below the domain name. A subdomain is every domain in
thenamespacebelowtherootdomain.
Typically, each domain has a domain administrator responsible for coordinating
and managing the domain. The domain administrator registers a second-level or
lower domain by interacting with the domain administrator in the next higher-level
domain.
The domain administrator’s duties include:
• Ensuring reliable service
• Ensuring that the BIND data is current
• Taking prompt action when necessary, for example, if protocols are violated or
other serious issues occurs
8–2 Domain Name System/BIND (DNS/BIND)