Cite this BCP: TXTBCP 222 contains the following RFCs:
|RFC 8552, BCP 222||Scoped Interpretation of DNS Resource Records through "Underscored" Naming of Attribute Leaves||D. Crocker||March 2019||Errata||Best Current Practice|
|RFC 8553, BCP 222||DNS Attrleaf Changes: Fixing Specifications That Use Underscored Node Names||D. Crocker||March 2019||Updates RFC 2782, RFC 3263, RFC 3529, RFC 3620, RFC 3832, RFC 3887, RFC 3958, RFC 4120, RFC 4227, RFC 4386, RFC 4387, RFC 4976, RFC 5026, RFC 5328, RFC 5389, RFC 5415, RFC 5518, RFC 5555, RFC 5617, RFC 5679, RFC 5766, RFC 5780, RFC 5804, RFC 5864, RFC 5928, RFC 6120, RFC 6186, RFC 6376, RFC 6733, RFC 6763, RFC 7208, RFC 7489, RFC 8145||Best Current Practice|
Abstract of RFC 8552
Formally, any DNS Resource Record (RR) may occur under any domain name. However, some services use an operational convention for defining specific interpretations of an RRset by locating the records in a DNS branch under the parent domain to which the RRset actually applies. The top of this subordinate branch is defined by a naming convention that uses a reserved node name, which begins with the underscore character (e.g., "_name"). The underscored naming construct defines a semantic scope for DNS record types that are associated with the parent domain above the underscored branch. This specification explores the nature of this DNS usage and defines the "Underscored and Globally Scoped DNS Node Names" registry with IANA. The purpose of this registry is to avoid collisions resulting from the use of the same underscored name for different services.
Abstract of RFC 8553
Using an underscore for a prefix creates a space for constrained interoperation of resource records. Original uses of an underscore character as a domain node name prefix were specified without the benefit of an IANA registry. This produced an entirely uncoordinated set of name-creation activities, all drawing from the same namespace. A registry for these names has now been defined by RFC 8552. However, the existing specifications that use underscored naming need to be modified in order to be in line with the new registry. This document specifies those changes. The changes preserve existing software and operational practice, while adapting the specifications for those practices to the newer underscore registry model.
For the definition of Status, see RFC 2026.
For the definition of Stream, see RFC 4844.