# What is DNS?

The **DNS (Domain Name System )** is a core internet protocol that translates human-readable domain names into numerical IP addresses required for network communication.\
It acts as a distributed, hierarchical database that allows browsers, applications, and APIs to locate online resources efficiently.\
Within **Medianova’s infrastructure**, DNS provides the critical mapping layer that directs user requests to the correct CDN Resource or Redirect endpoint, ensuring consistent performance and service availability.

#### **How DNS Works**

DNS operates through a global hierarchy of **root**, **top-level domain (TLD)**, and **authoritative name servers**, each responsible for part of the name resolution process.\
When a query is initiated, recursive resolvers traverse this hierarchy, cache responses, and return the authoritative record for the requested domain.

```plaintext
Root (.)
 └── TLDs (com, org, net, tr)
      └── Domains (example.com)
           └── Subdomains (cdn.example.com)
```

Each DNS record type serves a specific purpose:

* **A / AAAA:** Map domain names to IPv4 or IPv6 addresses.
* **CNAME:** Alias one domain to another, often used to connect a branded hostname (e.g., `cdn.yourdomain.com`) to a Medianova CDN Resource (`yourzonename.mncdn.com`).
* **MX / TXT / SRV:** Support email routing, domain verification, and service discovery.

For additional details on configuring CNAME records within Medianova, see [CNAME & SSL](https://clients.medianova.com/products/performance-cdn/static-content-delivery/advanced-configuration/cname-and-ssl).

#### **DNS in the Medianova**

DNS is not just a prerequisite for routing traffic — it is an integrated layer of Medianova’s delivery architecture.

**Within Medianova services, DNS enables:**

* **Zone-based configuration:** Each CDN Resource or Redirect domain operates within a defined DNS Zone.
* **Anycast routing:** Queries are automatically resolved through the closest available authoritative node for improved reliability and reduced lookup latency.
* **Secure HTTPS mapping:** Combined with SSL/TLS certificates to ensure encrypted access.
* **Redirect operations:** Medianova’s Redirect feature uses DNS mapping for efficient domain-level forwarding.

By integrating these mechanisms, Medianova ensures optimized name resolution, minimized propagation delays, and high query availability across its global network.

#### **Technical Summary**

<table><thead><tr><th width="206">Component</th><th>Description</th></tr></thead><tbody><tr><td><strong>Protocol</strong></td><td>Primarily UDP (port 53) for queries, TCP for zone transfers and large payloads</td></tr><tr><td><strong>Caching</strong></td><td>Reduces recursive lookup time and query load</td></tr><tr><td><strong>Record Types</strong></td><td>A, AAAA, CNAME, MX, TXT, SRV, PTR</td></tr><tr><td><strong>Security Extensions</strong></td><td>DNSSEC, CAA, TLSA support</td></tr><tr><td><strong>Integration</strong></td><td>Used by Medianova CDN, Redirect, and CNAME &#x26; SSL configurations</td></tr></tbody></table>