GeoDNS
DNS response selection based on the estimated location or network of the requester. The decision may use resolver address, ECS data, latency, policy regions, or anycast ingress.
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Browse the glossaryDNS glossary — page 6
311 definitions associated with DNS.
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Page 6 of 13Glue
Address records published in a parent zone to provide the addresses of delegated child name servers when those server names cannot otherwise be resolved without circular dependency. Glue is not authoritative child-zone data.
Read definitionGlue record
An A or AAAA record placed in a parent zone to support a delegation. Resolvers treat glue differently from authoritative answer data and apply bailiwick rules before caching it.
Read definitionGSLB
Global Server Load Balancing, the use of DNS and health, geography, topology, or load information to direct clients to an appropriate application endpoint. Some vendors call it global traffic management.
Read definitionGSS-TSIG
A method that uses Generic Security Service mechanisms, commonly Kerberos, to authenticate DNS dynamic updates with TSIG-style transaction protection. It underpins secure dynamic update in many Active Directory environments.
Read definitionHealth check
An active or passive test used to decide whether an endpoint should receive traffic. GSLB systems may monitor TCP, HTTP, DNS, application content, or external telemetry before publishing an answer.
Read definitionHidden primary
A primary authoritative server that is not listed in the zone's public NS RRset and is normally reachable only by secondaries or management systems. It centralizes updates while reducing public exposure.
Read definitionHINFO record
A Host Information record that can describe CPU and operating system text for a host. It is rarely used on the public Internet because the information can become stale or reveal unnecessary detail.
Read definitionHostname
A name used to identify a host, often a single label or an FQDN. Hostname syntax rules are more restrictive than the full range of labels permitted by the DNS protocol.
Read definitionHTTPS record
The HTTPS service binding record, a specialized SVCB form for HTTPS endpoints. It can advertise alternative endpoints, protocols, ports, encrypted-client-hello parameters, and address hints.
Read definitionIDN
Internationalized Domain Name, a domain name that represents Unicode characters using an ASCII-compatible encoding in DNS. User interfaces may display native characters while the wire form uses A-labels beginning with xn--.
Read definitionIDNA
Internationalized Domain Names in Applications, the standards framework that maps, validates, and converts Unicode labels for use with the ASCII DNS protocol. Application behavior and registry policy both affect which names are valid.
Read definitionImplied apex NS
An informal description of the authoritative NS RRset located at a zone apex. The parent delegation NS and child apex NS should be operationally consistent, though they are separate RRsets.
Read definitionIN class
The Internet DNS class, numeric value 1, used by nearly all ordinary DNS resource records and queries. Other classes exist but are rarely used for production Internet naming.
Read definitionIn-addr.arpa
The DNS reverse-mapping domain for IPv4. Address octets are reversed as labels below in-addr.arpa, with zone boundaries aligned to delegated portions of address space.
Read definitionIn-bailiwick
A name that falls within the relevant zone or delegation boundary. A child name server whose name is inside the child zone normally requires glue in the parent.
Read definitionInternal DNS
DNS infrastructure or data intended for an organization's internal clients and private namespaces. Internal DNS commonly supports recursion, private zones, Active Directory, service discovery, and split responses.
Read definitionIp6.arpa
The DNS reverse-mapping domain for IPv6. Each hexadecimal nibble of the 128-bit address is reversed as a label beneath ip6.arpa.
Read definitionIterative query
A query for which the server returns the best answer or referral it currently has without taking responsibility for completing resolution on the client's behalf. Recursive resolvers send iterative queries to authoritative infrastructure.
Read definitionIterative resolution
The process of following referrals from the root, TLD, and lower authoritative servers until an answer or authoritative negative response is obtained. Results are cached according to TTL.
Read definitionIXFR
An incremental zone transfer that sends changes between SOA serial versions when both servers have suitable history. It can be much smaller than AXFR, with fallback to full transfer when needed.
Read definitionJournal
A change log used by a DNS server to support dynamic update recovery and incremental zone transfers. Journal file formats and retention are implementation-specific.
Read definitionKnot DNS
An open-source authoritative DNS server developed by CZ.NIC, designed for high-performance authoritative service and DNSSEC operation. It is distinct from Knot Resolver.
Read definitionKnot Resolver
An open-source caching and validating recursive resolver developed by CZ.NIC. It supports modular policy and modern DNS transports.
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