The DNS is a hierarchical, distributed database. The database itself consists of resource records (RRs), which primarily consist of a DNS name, a record type, and data values that are associated with that record type. To resolve names, servers consult their. The zones contain RRs that make up the resource information associated with the DNS domain.
• The first record in any database file must be the Start of Authority Record (SOA) which defines the general parameters for the DNS zone. All SOA records follow a number of rules:
■ The @ symbol in a database file indicates "this server".
■ in indicates an Internet record.
■ Any host name not terminated with a period (.) will be appended with the root domain.
■ The @ symbol is replaced by a period (.) in the e-mail address of the administrator.
■ Parentheses ( () ) must enclose line breaks that span more than one line.
• The Name Server Record (NS) lists the additional DNS name servers. A database file may contain more than one NS record.
• A Host Address Record (A), also referred to as a Host Record, associates a host name to its IP address. Host records will comprise most of the database file and will list all hosts within the zone.
• A Canonical NAME Record (CNAME) associates more than one host name with a single IP address. This is sometimes referred to as aliasing.
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