DDNS
Dynamic DNS, the controlled creation, modification, or deletion of DNS records without manually editing a zone file. DHCP servers and clients commonly use DNS UPDATE to register address and pointer records.
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311 definitions associated with DNS.
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Page 3 of 13Delegation
The relationship created when a parent zone publishes NS records that identify the authoritative servers for a child zone. A delegation may also require glue address records in the parent.
Read definitionDelegation-centric zone
A zone whose main purpose is publishing delegations rather than ordinary endpoint data, such as a large parent zone operated by a registry. Operational choices for signing, transfers, and automation may differ from host-oriented zones.
Read definitionDHCID record
A DNS record that stores a digest representing a DHCP client identity and name association. It helps DHCP servers detect ownership conflicts during coordinated dynamic DNS updates.
Read definitionDKIM
DomainKeys Identified Mail, an email-authentication method that adds a cryptographic signature to a message. The public verification key is published in a DNS TXT record beneath a selector-specific name.
Read definitionDKIM selector
A label identifying which DKIM public key should be retrieved for a signed email. The lookup name uses selector._domainkey followed by the signing domain.
Read definitionDMARC
Domain-based Message Authentication, Reporting, and Conformance, a policy framework that evaluates SPF and DKIM alignment and publishes policy and reporting addresses in DNS TXT records.
Read definitionDNAME record
A Delegation Name record redirects an entire subtree of names to another subtree, unlike CNAME which aliases a single owner name. Resolvers synthesize a CNAME-like result for the queried descendant.
Read definitionDNS
The Domain Name System, a distributed hierarchical database and protocol used to map names to resource records. It supports far more than address lookup, including service discovery, email routing, delegation, policy, and security data.
Read definitionDNS amplification
A denial-of-service technique in which an attacker sends small spoofed queries that trigger larger DNS responses toward a victim. Open recursion, large UDP responses, DNSSEC data, and ANY behavior can increase the amplification factor.
Read definitionDNS anomaly
A query or response pattern that differs from expected behavior, such as sudden NXDOMAIN growth, unusual labels, rare record types, high entropy, or traffic from an unexpected client. An anomaly is a signal, not proof of malicious activity.
Read definitionDNS cache snooping
Techniques that infer whether a resolver recently looked up a name by observing its cache behavior or TTL. Restricting recursion and minimizing information leakage can reduce exposure.
Read definitionDNS class
The CLASS field associated with queries and resource records. IN is the normal Internet class, while other values are used for historical, diagnostic, or specialized purposes.
Read definitionDNS Cookies
An EDNS option that carries client and server cookies to improve transaction assurance and reduce off-path spoofing and reflection abuse without establishing a full session.
Read definitionDNS firewall
A policy enforcement layer that blocks, redirects, or otherwise controls DNS resolution based on domain intelligence, client identity, category, or behavior. RPZ is a common standards-based policy distribution mechanism.
Read definitionDNS flag day
A coordinated industry event after which participating DNS software stops accommodating a legacy or non-compliant behavior. The goal is to accelerate protocol hygiene by changing defaults at the same time.
Read definitionDNS forwarding proxy
A DNS intermediary that accepts client queries and sends them to another resolver, sometimes adding policy, caching, encryption, or protocol translation. Its exact recursion and validation behavior should be documented.
Read definitionDNS hijacking
Unauthorized alteration or interception of DNS behavior so users receive attacker-selected or policy-selected results. It can occur at registrars, authoritative servers, resolvers, endpoints, routers, or network interception points.
Read definitionDNS message
The protocol unit containing a DNS header and question, answer, authority, and additional sections. Queries and responses use the same overall format with flags indicating purpose and status.
Read definitionDNS name compression
A wire-format technique that replaces repeated domain-name suffixes with pointers to earlier positions in a DNS message. Incorrect compression processing has historically caused implementation vulnerabilities.
Read definitionDNS policy
Rules that influence how queries are answered or processed based on name, type, client, time, geography, health, or security intelligence. Examples include response policy zones, views, traffic steering, and filtering.
Read definitionDNS rebinding
An attack in which a domain's answers change so browser-originated traffic is redirected from an attacker-controlled host to an internal or local address. Resolver protections can block suspicious private or loopback answers for external names.
Read definitionDNS response rate limiting (RRL)
An authoritative-server defense that limits repeated similar responses, especially to spoofable UDP queries, to reduce participation in reflection attacks. Implementations usually allow some responses and may trigger truncation.
Read definitionDNS search list
An ordered set of suffixes a host may append to a relative name during local resolution. DHCP options 119 and 24 can distribute search lists for IPv4 and IPv6 respectively.
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