Web design software - The cache and primary statements have been converted
The cache and primary statements have been converted into zone paragraphs with type clauses of hint and master, respectively. The zone files do not need to be modified in any way; their syntax remains unchanged. The new configuration syntax allows for many new options that we haven’t covered here. If you’d like information on the new options, the best source of information is the documentation supplied with the BIND Version 8 source package. The DNS Database Files Master files included with named, like named.hosts, always have a domain associated with them, which is called the origin. This is the domain name specified with the cache and primary options. Within a master file, you are allowed to specify domain and host names relative to this domain. A name given in a configuration file is considered absolute if it ends in a single dot, otherwise it is considered relative to the origin. The origin by itself may be referred to using (@). The data contained in a master file is split up in resource records(RRs). RRs are the smallest units of information available through DNS. Each resource record has a type. A records, for instance, map a hostname to an IP address, and a CNAME record associates an alias for a host with its official hostname. To see an example, look at Example 6.11, which shows the named.hosts master file for the Virtual Brewery. Resource record representations in master files share a common format: [domain][ttl][class] type rdata Fields are separated by spaces or tabs. An entry may be continued across several lines if an opening brace occurs before the first newline and the last field is followed by a closing brace. Anything between a semicolon and a newline is ignored. A description of the format terms follows: domain This term is the domain name to which the entry applies. If no domain name is given, the RR is assumed to apply to the domain of the previous RR. ttl In order to force resolvers to discard information after a certain time, each RR is associated a time to live (ttl). The ttl field specifies the time in seconds that the information is valid after it has been retrieved from the server. It is a decimal number with at most eight digits. If no ttl value is given, the field value defaults to that of the minimum field of the preceding SOA record. class This is an address class, like IN for IP addresses or HS for objects in the Hesiod class. For TCP/IP networking, you have to specify IN. If no class field is given, the class of the preceding RR is assumed. type This describes the type of the RR. The most common types are A, SOA, PTR, and NS. The following sections describe the various types of RRs. rdata This holds the data associated with the RR. The format of this field depends on the type of RR. In the following discussion, it will be described for each RR separately. The following is partial list of RRs to be used in DNS master files. There are a couple more of them that we will not explain; they are experimental and of little use, generally. SOA This RR describes a zone of authority (SOA means “Start of Authority”). It signals that the records following the SOA RR contain authoritative information for the domain. Every master file included by a