Key Concepts & Terminology

Learn the core DNS concepts and how domains, zones, and records operate within Medianova’s DNS and CDN architecture.

Understanding DNS terminology is essential for configuring, troubleshooting, and maintaining high-availability content delivery. This page explains how key DNS components — such as domains, zones, and records — interact in the resolution process, and how they map directly to Medianova’s DNS and CDN Resource management system. Each concept is presented with both a standard definition and its role in the Medianova platform.

Domain

A domain is a named node within the DNS hierarchy. It provides a readable identifier for services without exposing their physical or IP-level location. Domains are structured from right to left:

Level	Example	Description
TLD	.com	Top-Level Domain
SLD	example	Second-Level Domain
Subdomain	www	Host or service label

A complete domain, when ending with a trailing dot (.), forms a Fully Qualified Domain Name (FQDN). Within Medianova, customer CDN resources are often accessed via custom subdomains such as cdn.yourdomain.com, mapped through a CNAME record to a Medianova hostname like yourzonename.mncdn.com. See CNAME & SSL.

Fully Qualified Domain Name (FQDN)

An FQDN uniquely identifies a host or service within the DNS hierarchy. It consists of a subdomain (or host), second-level domain, top-level domain, and an implicit root.

Example:

www.example.com.

Medianova CDN configurations frequently reference FQDNs to associate a CNAME record with a specific CDN Resource or Redirect domain. → See Redirect for domain-level forwarding examples.

Zone

A zone defines the administrative boundary for a portion of the DNS namespace. It includes:

• SOA (Start of Authority) record

• NS (Nameserver) records

• Resource records such as A, CNAME, TXT, or MX

A zone can represent an entire domain (e.g., example.com) or a delegated subdomain (e.g., media.example.com). In Medianova DNS, each customer-configured resource (CDN or Redirect) operates within its own zone, managed via the Medianova DNS Service.

Record

A DNS record is a data entry within a zone that maps a domain name to specific information — such as IP addresses, hostnames, or metadata. Each record includes:

• Name – Domain or subdomain the record applies to

• Type – Record category (e.g., A, MX, TXT)

• TTL – Cache duration in seconds

• Value – Target address or data

Example:

www.example.com. 3600 IN A 203.0.113.10

Medianova primarily uses A, AAAA, and CNAME records to connect user domains to CDN edge endpoints.

Nameserver

A nameserver stores and serves DNS zone data. There are two major types:

Type	Description	Medianova Context
Authoritative nameserver	Responds with verified zone records for a domain.	Medianova operates authoritative Anycast nameservers (ns1.medianova.com, ns2.medianova.com) for customer zones.
Recursive resolver	Resolves queries on behalf of clients by traversing the DNS hierarchy.	Typically external (e.g., 8.8.8.8, 1.1.1.1); interacts with Medianova authoritative servers during lookups.

Authoritative nameservers are the ultimate source of truth for a zone, while recursive resolvers handle caching and query acceleration.

Delegation

Delegation transfers administrative control of a subdomain to a different set of nameservers. This is achieved by defining NS records in the parent zone that point to the authoritative nameservers of the child zone.

Example:

shop.example.com.  IN  NS  ns1.shopdns.net.
shop.example.com.  IN  NS  ns2.shopdns.net.

Medianova supports delegation for organizations managing multiple environments — such as separating cdn.example.com for CDN traffic from mail.example.com for mail services.

TTL (Time To Live)

TTL defines how long a DNS record can be cached by resolvers and clients before a refresh is required. Short TTLs allow faster propagation of changes but increase query volume; longer TTLs reduce DNS load but delay updates.

In Medianova DNS, TTL values can be adjusted per record to balance performance and flexibility — especially useful for Redirects or failover configurations that require rapid updates.

Recursive Resolver vs. Authoritative Nameserver

Function	Recursive Resolver	Authoritative Nameserver
Role	Intermediary client-side resolver	Source of truth for domain or zone
Caching	Yes (per TTL)	No
Starts from Root?	Yes	No
Answers Final Queries?	Only if cached	Yes
Examples	8.8.8.8, 1.1.1.1	ns1.medianova.com, ns2.medianova.com

Fully Qualified Domain Name (FQDN)

An FQDN is an absolute, unambiguous name that fully specifies a location in the DNS hierarchy. It includes:

• Subdomain or host (e.g., www)

• Second-level domain (e.g., example)

• TLD (e.g., com)

• Implicit root (.)

Example: www.example.com. is an FQDN, while example.com is a relative name without context.

Zone

A zone defines a set of DNS records under a single administrative boundary. While a domain is a naming concept, a zone is a configuration unit that contains:

• An SOA (Start of Authority) record

• NS (Nameserver) records

• Resource records (A, CNAME, TXT, etc.)

A zone can span an entire domain (e.g., example.com) or a delegated subdomain (e.g., internal.example.com).

Zones are hosted on authoritative nameservers and define how DNS queries should be answered for the records they contain.

Record

A record is a single entry within a DNS zone. Each record maps a domain name to a specific piece of information—most commonly an IP address, but also mail servers, service metadata, or cryptographic keys.

Every DNS record includes:

• Name: The label or subdomain it applies to

• Type: The kind of record (e.g., A, MX, TXT)

• TTL: How long the record can be cached

• Value: The actual data (e.g., IP address, hostname)

Example:

www.example.com. 3600 IN A 203.0.113.10

Nameserver

A nameserver is a server that stores and serves DNS zone data. There are two main types:

• Authoritative nameserver: Responds with the actual DNS records for a domain or zone.

• Recursive resolver: Acts on behalf of clients to resolve queries, starting from the root if necessary.

Authoritative nameservers are the source of truth for a zone, while recursive resolvers are intermediaries that cache and accelerate lookups.

Delegation

Delegation occurs when a zone administrator assigns authority over a subdomain to a different set of nameservers. This is implemented by placing NS records in the parent zone pointing to the nameservers of the child zone.

For example:

• example.com may delegate shop.example.com to another DNS provider or system.

• The parent zone retains the NS record, but the child zone becomes independently administrable.

TTL (Time To Live)

TTL is a numeric value (in seconds) that defines how long a DNS record may be cached by resolvers and clients.

• Short TTLs allow rapid changes but increase query traffic.

• Long TTLs reduce load but may delay propagation of updates.

TTL strategy is a critical component of DNS performance and reliability tuning.

Recursive Resolver vs Authoritative Nameserver

Function	Recursive Resolver	Authoritative Nameserver
Role	Client-side intermediary	Source of truth for a domain/zone
Caching	Yes (per TTL)	No
Starts from Root?	Yes	No
Answers Final Queries?	Only if cached	Yes (with exact data)
Examples	8.8.8.8 (Google), 1.1.1.1 (Cloudflare)	ns1.medianova.com, ns2.example.com