The following paragraphs will introduce some concepts used in ldns. It is assumed that the reader is familiar with DNS (knowledge of DNSSEC is not a problem).
Take for instance the following RR:
open.nlnetlabs.nl 8600 IN A 213.154.224.1This RR consists out of five elements:
the ownername of the RR
the TTL of the RR
the class of the RR
the type of the RR
1 rdata field, in this case with the address
To begin with the last element, ldns calls that a RDATA FIELD, or rdf. This is the smallest type in ldns. An RR's rdata consists of 1 or several rdf's. All these rdf's have a type, in the case of an A record, this type is LDNS_RDF_TYPE_A. The data in a rdf is stored in network byte order.
This is the type of the whole RR, this type is called LDNS_RR_TYPE_A in ldns
The class. Other possible values are CH, and HS. But only the IN class is used on the Internet.
The TTL of a RR, stored in host order.
The ownername of the RR, this owner name is stored in wire data, this this particaliar name is stored as 04open09nlnetlabs02nl00.
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