40 definitions beginning with C.
40 terms
A Certification Authority Authorization record states which certificate authorities are permitted to issue certificates for a domain and can define incident-reporting contacts. Certificate authorities are expected to check it before issuance.
Read definitionTemporary storage of DNS responses and related metadata by a resolver or intermediary. Cached data is reused until its TTL expires or the cache is cleared, replaced, or invalidated.
Read definitionA query answered from cached data without contacting an upstream authoritative server. A high cache-hit rate can reduce latency and upstream load, though the right rate depends on workload and TTLs.
Read definitionA query for which the resolver does not have usable cached data and must perform resolution or forwarding. Misses increase upstream traffic and usually add latency.
Read definitionThe insertion of false DNS data into a resolver cache so future clients receive an attacker-chosen answer. Defenses include strong transaction matching, source-port randomization, DNSSEC validation, cookies, and hardened bailiwick processing.
Read definitionA resolver that stores responses and reuses them for later queries. It may perform full iterative resolution or forward queries to another resolver.
Read definitionThe selected true or target name for an alias. A CNAME record points an alias owner name to a canonical target name, though the target can itself lead through another alias.
Read definitionA deterministic ordering and representation of DNS names and record data used when creating or verifying DNSSEC signatures. It ensures different implementations calculate the same signed data.
Read definitionForecasting when address pools, prefixes, DHCP capacity, or DNS infrastructure will need expansion. Useful inputs include utilization, growth rate, lease churn, query rate, and failure-domain requirements.
Read definitionLarge-scale address translation used by service providers to share public IPv4 addresses among customers, commonly using 100.64.0.0/10 on the provider side. CGN complicates attribution and end-to-end address visibility.
Read definitionA special DNS zone that distributes a catalog of member zones and associated properties to participating authoritative servers. It can automate secondary-zone provisioning across a fleet.
Read definitionThe Checking Disabled bit in a DNS query asks a validating resolver to return data without enforcing DNSSEC validation failure for that transaction. It is typically used by a client that intends to validate independently.
Read definitionA Child DNSKEY record published by a child to request that the parent create or update a corresponding DS record. It is an alternative signal to CDS for automated delegation maintenance.
Read definitionA Child DS record published in a child zone to signal desired DS changes to the parent. It supports automated DNSSEC delegation maintenance when the parent follows a defined acceptance policy.
Read definitionA TLSA record binds a TLS service endpoint to an expected certificate or public key. It is the core DNS record used by DANE and is meaningful when protected by DNSSEC.
Read definitionThe sequence of validated signatures and delegation records that links a configured trust anchor to signed data. At a secure delegation, the parent's DS authenticates the child's DNSKEY set.
Read definitionA zone whose apex is below another zone in the namespace and is reached through a delegation from its parent. The child controls authoritative data at and below its apex except for delegated descendants.
Read definitionClassless Inter-Domain Routing, the use of variable-length prefixes rather than legacy address classes. CIDR notation combines an address with a prefix length, such as 10.20.0.0/16.
Read definitionA DNS protocol field that identifies a namespace class. IN, for Internet, is overwhelmingly the common class; others such as CH exist for specialized or historical uses.
Read definitionDHCP option 121, which supplies IPv4 routes as destination prefixes and next-hop routers. When present, clients generally use it instead of the older classful static route option 33.
Read definitionA classification used to apply DHCP policy based on information such as vendor class, user class, relay information, architecture, or custom expressions. Classes can select pools, options, lease times, or access rules.
Read definitionA DHCP option by which a client communicates its desired fully qualified domain name and dynamic-update preferences. The server can use it to coordinate forward and reverse DNS registration.
Read definitionAn identifier supplied by a DHCP client so the server can recognize it independently of the current link-layer address. DHCPv4 uses option 61, while DHCPv6 primarily uses a DUID.
Read definitionThe defined sequence of client states and transitions used to acquire, renew, rebind, release, or validate configuration. DHCPv4 examples include INIT, SELECTING, REQUESTING, BOUND, RENEWING, and REBINDING.
Read definitionFor a queried name that does not exist, the closest encloser is the longest existing ancestor name in the zone. It is central to wildcard processing and DNSSEC proofs of nonexistence.
Read definitionDNS services delivered through a cloud control plane, including authoritative hosting, recursive resolution, private zones, traffic management, and security policy. The data plane may be provider-managed and globally distributed.
Read definitionAddress planning and lifecycle management integrated with cloud accounts, virtual networks, subnets, and interfaces. It often reconciles provider inventory with an enterprise source of truth.
Read definitionA sequence in which a queried alias points to another name that may itself be an alias before reaching terminal data. Long chains add latency and increase the chance of loops, broken targets, or policy differences.
Read definitionA provider feature that follows a configured alias target at the authoritative platform and returns address records to the client. It is often used at the zone apex where an ordinary CNAME would conflict with required SOA and NS data.
Read definitionA Canonical Name record makes its owner name an alias for a target name. With limited DNSSEC-related exceptions, other data should not coexist at the same owner name.
Read definitionA DNSSEC design that reduces or avoids the traditional zone-enumeration and response-size costs of NSEC or NSEC3 while still proving nonexistence. Specific mechanisms depend on the authoritative implementation and standards in use.
Read definitionA forwarding rule that sends queries for selected domains to specific upstream resolvers instead of using the normal recursive path. It is commonly used between organizations, Active Directory forests, clouds, and isolated environments.
Read definitionA difference between intended configuration and the state actually deployed across servers, appliances, cloud services, or data stores. Drift can create inconsistent answers, overlapping allocations, and failover risk.
Read definitionA check performed before or around address assignment to see whether an address is already in use. DHCPv4 may use ICMP echo, ARP probes, or client feedback, while IPv6 clients use Duplicate Address Detection.
Read definitionAn aggregate network object used to organize or subdivide address space but not necessarily treated as a directly usable subnet. Products may call it a network container, aggregate, block, or parent prefix.
Read definitionThe systems and protocols that create, distribute, and manage service state, such as zone data, policies, IPAM objects, and DHCP configuration. It is distinct from the data plane that answers queries or leases.
Read definitionA lightweight DNS transaction token carried in an EDNS option to help a server verify that a client can receive traffic at its claimed address. DNS Cookies can reduce spoofed-query abuse and improve transaction matching.
Read definitionA modular DNS server commonly used for service discovery in Kubernetes and other cloud-native environments. Its behavior is defined by a chain of plugins.
Read definitionA Child-to-Parent Synchronization record allows a child zone to signal selected delegation-data changes, such as NS and related address records, to its parent under an agreed automation policy.
Read definitionA centrally operated user-facing recursive DNS service, often used as an organizational resolver platform. The acronym is less universal than common terms such as recursive resolver.
Read definition