Label
A component of a domain name separated by dots in presentation form. On the wire, a standard label is length-prefixed and generally limited to 63 octets.
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Browse the glossaryDNS glossary — page 7
311 definitions associated with DNS.
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311 matching terms
Page 7 of 13Lame delegation
A delegation that points to a server that is not authoritative for the delegated zone or cannot serve it correctly. Lame delegations cause resolution delays, intermittent failures, and operational noise.
Read definitionLOC record
A Location record encodes geographic coordinates, altitude, size, and precision for a domain name. It is not widely deployed and should not be relied on as a current asset-location system.
Read definitionLocal data
DNS records or policy answers configured directly in a resolver rather than learned from public authoritative resolution. Examples include local zones, hosts entries, block responses, and internal overrides.
Read definitionLocal zone
A resolver-controlled zone that provides authoritative-like local answers, negative responses, redirects, or policy for a selected namespace. It does not necessarily exist in the global DNS hierarchy.
Read definitionLocal-host zone
A locally served namespace used for host-specific or network-specific answers, often to override external data or provide private names. The term and exact semantics vary by resolver implementation.
Read definitionManaged DNS
A DNS service operated by a provider or centralized platform on behalf of the zone owner. Management, signing, distribution, scaling, and availability are delivered through a service control plane.
Read definitionMaster file
The standardized text representation of DNS zone data, also called zone-file format. Modern terminology favors primary and secondary for server roles rather than master and slave.
Read definitionMaximum DNS message size
DNS over UDP was originally limited to 512 bytes, while EDNS allows larger advertised payloads. DNS over TCP and other stream transports can carry messages up to 65,535 bytes, subject to protocol framing and implementation limits.
Read definitionMicrosoft DNS
The DNS Server role and related client components in Windows Server and Active Directory environments. It supports AD-integrated zones, secure dynamic update, conditional forwarding, policies, DNSSEC, and standard DNS protocols.
Read definitionMNAME
The first domain-name field in the SOA record, conventionally naming the zone's primary source server. Modern distributed and hidden-primary architectures can make the literal operational role more nuanced.
Read definitionMulti-primary
An architecture in which more than one authoritative source can accept changes for the same zone and a separate replication system reconciles them. Active Directory-integrated DNS is a common example.
Read definitionMX record
A Mail Exchange record identifies mail servers for a domain and assigns each a preference value. Lower preference values are tried first, with equal values treated as alternatives.
Read definitionName error
The original DNS RCODE description for NXDOMAIN, indicating that the queried domain name does not exist according to an authoritative response. It is distinct from an existing name that lacks the requested record type.
Read definitionName server
A DNS server that answers queries from authoritative data, recursive processing, cache, forwarding, or local policy. The term alone does not specify the server's role.
Read definitionName 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.
Read definitionNamed
The traditional daemon process name for BIND DNS server. Administrators use configuration files and tools such as rndc to control it.
Read definitionNaming authority
The organization or system with administrative control over a namespace or zone. Authority is established operationally through delegation and control of authoritative data.
Read definitionNAPTR record
A Naming Authority Pointer record applies ordered rewriting rules to discover services or transform identifiers. It is used in ENUM, SIP, and other naming systems, often together with SRV records.
Read definitionNegative answer
An authoritative response indicating that a name does not exist or that the name exists but lacks the requested type. Resolvers can cache negative answers using the SOA information and applicable rules.
Read definitionNegative caching
Caching of authoritative negative answers so repeated nonexistent-name or missing-type queries do not repeatedly reach authoritative servers. The negative TTL is derived from the SOA according to current rules.
Read definitionNext closer name
In wildcard and DNSSEC processing, the name one label longer than the closest encloser and on the path toward the original query name. It is used to prove that no closer matching name exists.
Read definitionNibble boundary
A boundary aligned on a four-bit hexadecimal digit. IPv6 reverse DNS is simplest when prefixes are delegated on nibble boundaries because each label in ip6.arpa represents one hexadecimal digit.
Read definitionNo-refresh interval
The first phase of Microsoft DNS aging during which repeated refreshes do not update a record's timestamp. It reduces replication traffic while still allowing actual record changes.
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