DNS Rdata

An Rdata is typed data in one of the known DNS datatypes, for example type A, the IPv4 address of a host or type MX, how to route mail. Unlike like the DNS RFC concept of RR, an Rdata is not bound to an owner name. Rdata is immutable.

Rdata of the same type can be grouped into an unnamed set, an Rdataset, or into a named set, an RRset.