DNS Advanced Topics and Best Practices
Expert-defined terms from the Certified Professional in Domain Name System (DNS) course at London School of Business and Administration. Free to read, free to share, paired with a professional course.
AAAA Record #
The AAAA record is a type of DNS record that maps a domain name to an IPv6 address. It is similar to the A record, which maps a domain name to an IPv4 address. The AAAA record is used to support IPv6 connectivity and is essential for websites and applications that need to be accessible over IPv6 networks. Related terms: A record, IPv6, IPv4.
AD DNS #
AD DNS refers to the Active Directory Domain Name System, which is a DNS server that is integrated with the Active Directory service in Windows. AD DNS is used to provide DNS services to Active Directory domains and is essential for Active Directory authentication and authorization. Related terms: Active Directory, DNS server.
Anycast #
Anycast is a type of DNS routing that allows multiple DNS servers to share the same IP address. Anycast is used to provide load balancing and fault tolerance for DNS services, and is commonly used by large organizations and service providers. Related terms: Load balancing, fault tolerance.
Authority #
In the context of DNS, authority refers to the DNS server that is responsible for a particular domain or zone. The authority DNS server is the primary source of information for the domain or zone and is used to resolve DNS queries. Related terms: DNS server, zone.
Authoritative Name Server #
An authoritative name server is a DNS server that has the authority to answer DNS queries for a particular domain or zone. Authoritative name servers are typically maintained by the domain owner or service provider and are used to provide authoritative answers to DNS queries.
BIND #
BIND is a popular open-source DNS server software that is widely used on Unix-based systems. BIND is known for its flexibility and customizability, and is often used by organizations that require a high degree of control over their DNS services. Related terms: DNS server, open-source.
Caching #
Caching is a technique used by DNS servers to store frequently accessed DNS records in memory. Caching is used to improve the performance of DNS services by reducing the number of DNS queries that need to be sent to authoritative name servers. Related terms: DNS server, cache.
Canonical Name Record #
A canonical name record, also known as a CNAME record, is a type of DNS record that maps an alias or nickname to a canonical name. CNAME records are used to provide an alternative name for a domain or host, and are commonly used for load balancing and fault tolerance. Related terms: DNS record, alias.
Certificate Authority #
A certificate authority is an organization that issues digital certificates to verify the identity of a domain or organization. Certificate authorities are used to provide trust and authentication for secure communication over the internet. Related terms: Digital certificate, SSL/TLS.
Classless Inter #
Domain Routing: Classless inter-domain routing, also known as CIDR, is a technique used to improve the efficiency of IP address allocation. CIDR is used to allow multiple IP addresses to be represented by a single IP address prefix, and is commonly used by internet service providers. Related terms: IP address, routing.
Client #
Server Model: The client-server model is a communication model that is used by DNS services. In the client-server model, a client (such as a web browser) sends a DNS query to a server (such as a DNS server), and the server responds with the requested information. Related terms: DNS query, DNS server.
Conditional Forwarder #
A conditional forwarder is a type of DNS server that forwards DNS queries to other DNS servers based on the domain name. Conditional forwarders are used to provide flexible and scalable DNS services, and are commonly used by large organizations. Related terms: DNS server, forwarder.
Delegation #
Delegation is the process of assigning authority for a subdomain to a separate DNS server. Delegation is used to provide autonomy and flexibility for subdomains, and is commonly used by organizations with complex DNS infrastructures. Related terms: Subdomain, DNS server.
Domain Name #
A domain name is a unique identifier for a website, email server, or other internet resource. Domain names are used to provide a memorable and user-friendly way to access internet resources, and are typically registered with a domain registrar. Related terms: Website, email server.
Domain Name System #
The domain name system, also known as DNS, is a global database that maps domain names to IP addresses. DNS is used to provide a scalable and flexible way to access internet resources, and is essential for the functioning of the internet. Related terms: Domain name, IP address.
Domain Registrar #
A domain registrar is an organization that registers and manages domain names on behalf of individuals and organizations. Domain registrars are accredited by ICANN and are responsible for maintaining the accuracy and integrity of domain name registrations. Related terms: Domain name, ICANN.
DNS Query #
A DNS query is a request sent by a client to a DNS server to resolve a domain name to an IP address. DNS queries are used to retrieve information from the DNS database, and are typically sent using the UDP protocol. Related terms: DNS server, UDP.
DNS Server #
A DNS server is a computer that runs DNS software and provides DNS services to clients. DNS servers are responsible for resolving DNS queries and providing authoritative answers to DNS queries. Related terms: DNS query, authoritative.
DNS Zone #
A DNS zone is a portion of the DNS database that is managed by a single DNS server. DNS zones are used to provide autonomy and flexibility for DNS services, and are commonly used by organizations with complex DNS infrastructures. Related terms: DNS server, domain name.
Dynamic DNS #
Dynamic DNS, also known as DDNS, is a service that allows DNS records to be updated in real-time. Dynamic DNS is used to provide flexible and scalable DNS services, and is commonly used by organizations with dynamic IP addresses. Related terms: DNS record, IP address.
EDNS #
EDNS is an extension to the DNS protocol that provides additional features and functionality for DNS services. EDNS is used to provide support for large DNS packets and extended DNS labels, and is commonly used by organizations with complex DNS infrastructures. Related terms: DNS protocol, DNS packet.
Forwarder #
A forwarder is a type of DNS server that forwards DNS queries to other DNS servers. Forwarders are used to provide load balancing and fault tolerance for DNS services, and are commonly used by large organizations. Related terms: DNS server, load balancing.
Glue Record #
A glue record is a type of DNS record that is used to provide additional information about a domain name. Glue records are used to provide support for delegation and are commonly used by organizations with complex DNS infrastructures. Related terms: DNS record, delegation.
Host Record #
A host record is a type of DNS record that maps a domain name to an IP address. Host records are used to provide basic DNS services and are commonly used by small organizations and individuals.
ICANN #
ICANN is the Internet Corporation for Assigned Names and Numbers, which is a non-profit organization that oversees the DNS and IP address allocation. ICANN is responsible for maintaining the integrity and security of the DNS and IP address allocation, and is commonly used by organizations and individuals that require DNS and IP address services. Related terms: DNS, IP address.
IP Address #
An IP address is a unique identifier for a device on a network. IP addresses are used to provide a way to address devices on a network and are essential for the functioning of the internet. Related terms: Network, device.
IPv4 #
IPv4 is the fourth version of the Internet Protocol, which is a communication protocol that is used to provide addressing and routing for devices on a network. IPv4 is commonly used by organizations and individuals that require internet connectivity, and is slowly being replaced by IPv6. Related terms: IPv6, internet.
IPv6 #
IPv6 is the sixth version of the Internet Protocol, which is a communication protocol that is used to provide addressing and routing for devices on a network. IPv6 is designed to provide improved security and scalability compared to IPv4, and is slowly being adopted by organizations and individuals that require internet connectivity. Related terms: IPv4, internet.
Load Balancing #
Load balancing is a technique that is used to distribute traffic across multiple servers to improve performance and availability. Load balancing is commonly used by large organizations that require high-availability and scalability for their applications and services. Related terms: Server, traffic.
Mail Exchanger Record #
A mail exchanger record, also known as an MX record, is a type of DNS record that maps a domain name to a mail server. MX records are used to provide email services and are commonly used by organizations and individuals that require email connectivity. Related terms: DNS record, mail server.
Name Server #
A name server is a type of DNS server that provides DNS services to clients. Name servers are responsible for resolving DNS queries and providing authoritative answers to DNS queries.
NS Record #
An NS record is a type of DNS record that maps a domain name to a name server. NS records are used to provide delegation and are commonly used by organizations with complex DNS infrastructures.
PTR Record #
A PTR record is a type of DNS record that maps an IP address to a domain name. PTR records are used to provide reverse DNS services and are commonly used by organizations and individuals that require reverse DNS connectivity. Related terms: DNS record, reverse DNS.
Recursive Query #
A recursive query is a type of DNS query that is sent by a client to a DNS server to resolve a domain name to an IP address. Recursive queries are used to retrieve information from the DNS database, and are typically sent using the UDP protocol. Related terms: DNS query, UDP.
Reverse DNS #
Reverse DNS is a type of DNS service that maps an IP address to a domain name. Reverse DNS is used to provide security and authentication for email and other applications, and is commonly used by organizations and individuals that require reverse DNS connectivity.
Root Server #
A root server is a type of DNS server that provides DNS services for the root zone of the DNS. Root servers are responsible for resolving DNS queries for the root zone and are commonly used by organizations and individuals that require DNS connectivity. Related terms: DNS server, root zone.
Secondary DNS #
Secondary DNS is a type of DNS service that provides backup and redundancy for DNS services. Secondary DNS is used to provide high-availability and scalability for DNS services, and is commonly used by large organizations that require high-availability and scalability for their applications and services. Related terms: DNS service, high-availability.
Server Cluster #
A server cluster is a group of servers that work together to provide high-availability and scalability for applications and services. Server clusters are commonly used by large organizations that require high-availability and scalability for their applications and services. Related terms: Server, high-availability.
SOA Record #
An SOA record is a type of DNS record that provides information about a DNS zone. SOA records are used to provide administration and management for DNS zones, and are commonly used by organizations with complex DNS infrastructures. Related terms: DNS record, DNS zone.
Split Brain #
Split brain is a condition that occurs when a DNS server becomes desynchronized with its primary DNS server. Split brain is used to describe a situation where a DNS server is providing inconsistent or outdated information, and is commonly used by organizations that require high-availability and scalability for their DNS services. Related terms: DNS server, desynchronized.
SRV Record #
An SRV record is a type of DNS record that maps a domain name to a service. SRV records are used to provide information about services such as email and voice over IP, and are commonly used by organizations and individuals that require service discovery. Related terms: DNS record, service.
Subdomain #
A subdomain is a subset of a domain name that is used to provide additional functionality or services. Subdomains are commonly used by organizations and individuals that require flexible and scalable DNS services, and are used to provide autonomy and flexibility for subdomains. Related terms: Domain name, DNS services.
Time To Live #
Time to live, also known as TTL, is a value that is used to determine how long a DNS record is cached by a DNS server. TTL is used to provide control over the cache duration of DNS records, and is commonly used by organizations that require fine-grained control over their DNS services. Related terms: DNS record, cache.
Top #
Level Domain: A top-level domain, also known as a TLD, is the highest-level domain in the DNS hierarchy. TLDs are used to provide a way to organize and structure the DNS, and are commonly used by organizations and individuals that require DNS connectivity. Related terms: DNS, domain name.
TXT Record #
A TXT record is a type of DNS record that is used to provide additional information about a domain name. TXT records are commonly used by organizations and individuals that require custom DNS services, and are used to provide information such as SPF and DKIM records. Related terms: DNS record, SPF.
UDP #
UDP is a transport protocol that is used to send DNS queries and responses. UDP is commonly used by DNS servers and clients to send and receive DNS queries and responses, and is known for its fast and efficient transmission of data. Related terms: DNS query, transport protocol.
Zone File #
A zone file is a file that contains the DNS records for a DNS zone. Zone files are used to provide administration and management for DNS zones, and are commonly used by organizations with complex DNS infrastructures. Related terms: DNS zone, DNS record.
Zone Transfer #
A zone transfer is the process of transferring a DNS zone from one DNS server to another. Zone transfers are used to provide backup and redundancy for DNS services, and are commonly used by organizations that require high-availability and scalability for their DNS services. Related terms: DNS server, high-availability.