DO bit
The DNSSEC OK bit in the EDNS OPT record indicates that a requester can receive DNSSEC-related records in the response. It does not by itself request or prove validation.
Category glossary
Search all termsEDNS
6 definitions associated with EDNS.
ECS
EDNS Client Subnet, an EDNS option that lets a resolver include part of a client's network prefix in an upstream query so an authoritative service can tailor the answer geographically. It can improve content localization but reduces privacy and cache efficiency.
EDE
Extended DNS Error, an EDNS option that adds a more specific reason to a DNS response, such as blocked, stale answer, DNSSEC bogus, or network error. The normal RCODE remains present.
Name server identifier (NSID)
An EDNS option by which a requester asks the server to return an implementation-defined identifier for the responding instance. It is useful when many servers share an anycast or load-balanced address.
NSID
The abbreviation for Name Server Identifier, an EDNS option used to identify the responding server instance behind a shared service address.
OPT record
A pseudo-resource-record used to carry EDNS metadata in the additional section of a DNS message. Its class field advertises UDP payload size, while TTL bits carry extended RCODE, version, and flags.