[DNS] More intro details on different DNS setups (#18526)

* Move Concepts higher in get-started and add placeholder entry

* Add Auth DNS and review concepts for Domain, Registrar, and Zone

* Move nameserver def higher and solve overlap with Auth DNS

* Fill in DNS setups concept, applying Primary more prominently

* Review concepts and missing link to partial-setup

* Fix typo

* Update zone-setups page title to align with concepts and Dash

* Link out to domain-configurations as per Abby suggestion

* Process suggestions from PCX review

src/content/docs/dns/concepts.mdx

@@ -9,29 +9,49 @@ head:
 
 ---
 
-This page defines and articulates key concepts that are relevant to the Cloudflare DNS service and are used in this documentation. For more concepts and broader descriptions, check out the [Cloudflare Learning Center](https://www.cloudflare.com/learning/dns/what-is-dns/).
+This page defines and articulates key concepts that are relevant to the Cloudflare DNS service and are used in this documentation. For more concepts and broader descriptions, refer to the [Cloudflare Learning Center](https://www.cloudflare.com/learning/dns/what-is-dns/).
 
 ## Domain
 
-Also known as domain name, a domain is the string of text that identifies a specific website, such as `google.com` or `facebook.com`. Every time you access a website from your web browser, a DNS query takes place and the domain name is mapped to the actual IP address where the website is hosted.
+Also known as domain name, a domain is the string of text that identifies a specific website, such as `google.com` or `facebook.com`. Every time you access a website from your web browser, a DNS query takes place and the DNS service maps the domain to the actual IP address where the website is [hosted](/fundamentals/setup/manage-domains/).
 
 ## Registrar
 
-Before you can start using the Cloudflare DNS service, you must first have a domain. This is achieved by using a service called registrar. As explained in our [Learning Center](https://www.cloudflare.com/learning/dns/glossary/what-is-a-domain-name-registrar/), a registrar handles the reservation of domain names as well as the assignment of IP addresses for those domains.
+Before you can start using the Cloudflare DNS service, you must first have a domain. This is achieved by using a service called registrar. As explained in our [Learning Center](https://www.cloudflare.com/learning/dns/glossary/what-is-a-domain-name-registrar/), a registrar handles the reservation of domain names.
 
-Cloudflare offers at-cost domain registration through [Cloudflare Registrar](/registrar/).
+Very often the same company that offers domain registration also offers web hosting and DNS management.
 
-## Zone
+You can register a domain name at cost through [Cloudflare Registrar](/registrar/). Every domain acquired through Cloudflare Registrar must also use Cloudflare as their [primary authoritative DNS](#authoritative-dns).
+
+## Nameserver
 
-DNS zone is an administrative concept used for delegating control over DNS settings for different domains, subdomains or a set of both. You can read more about this in the [specific Learning Center article](https://www.cloudflare.com/learning/dns/glossary/dns-zone/).
+Although the resolution of a DNS query involves a number of different servers, in this documentation nameserver usually refers to the Cloudflare authoritative nameservers. As explained in the [article about DNS server types](https://www.cloudflare.com/learning/dns/dns-server-types/), the authoritative nameserver is the last stop in the resolution of a DNS query.
 
-For the purpose of this documentation, keep in mind that each site added to a Cloudflare account is listed in the account home page as a zone. The exact properties and behaviors of your zone depend on its [setup option](/dns/zone-setups/).
+Refer to [Nameservers](/dns/nameservers/) for details on the different nameserver offerings.
 
-## Nameserver
+## Authoritative DNS
+
+Authoritative DNS refers to the service whose nameservers provide the final information mapping a hostname (such as `example.com` or `blog.example.com`) to the IP address that hosts the corresponding content or resources.
+
+This is important because the performance of such authoritative DNS services determine how available, resilient, and performant your website or application is. Cloudflare DNS is an authoritative DNS service leveraging Cloudflare's global network. Refer to [How Cloudflare works](/fundamentals/concepts/how-cloudflare-works/) for details.
+
+## DNS setups
+
+It is also possible that one same company will use more than one DNS provider. Usually, this relates to making a domain more resilient - if one provider faces an outage, the nameservers operated by the other DNS provider will most likely still be available.
+
+In this context, you can have a primary DNS setup, when you use Cloudflare to manage your DNS records, or a [secondary DNS setup](/dns/zone-setups/zone-transfers/cloudflare-as-secondary/), when your DNS records are managed on a different provider and Cloudflare simply receives zone transfers containing your DNS records.
+
+When you have a primary DNS setup, you can either use only Cloudflare (also known as [Full setup](/dns/zone-setups/full-setup/)), or you can use Cloudflare and another provider, where the other provider is the one to receive [outgoing zone transfers](/dns/zone-setups/zone-transfers/cloudflare-as-primary/) from Cloudflare.
+
+Finally, as Cloudflare also works as a [reverse proxy](/fundamentals/concepts/how-cloudflare-works/#how-cloudflare-works-as-a-reverse-proxy), [partial (CNAME) setups](/dns/zone-setups/partial-setup/) can be used when you do not want Cloudflare to be [authoritative](#authoritative-dns) for your domain but you still want to proxy individual subdomains through Cloudflare.
+
+## Zone
+
+DNS zone is an administrative concept used for delegating control over a given domain and its subdomains. Read more in the ["What is a DNS zone?" Learning Center article](https://www.cloudflare.com/learning/dns/glossary/dns-zone/).
 
-Although the resolution of a DNS query involves a number of different servers, in this documentation nameserver usually refers to the Cloudflare authoritative nameservers. As explained in the [article about DNS server types](https://www.cloudflare.com/learning/dns/dns-server-types/), the authoritative nameserver is the last stop in the query, the server that returns the IP address for the requested domain.
+For the purpose of this documentation, keep in mind that each domain added to a Cloudflare account is listed in the account home page as a zone. The exact properties and behaviors of your zone depend on its [DNS setup](/dns/zone-setups/).
 
-When you have a domain using a [full setup](/dns/zone-setups/full-setup/), Cloudflare provides the authoritative nameservers for your domain. Refer to [Nameservers](/dns/nameservers/) for details on the different nameserver offerings.
+Also, different Cloudflare products and features are configurable at the zone level. Refer to [Fundamentals](/fundamentals/setup/manage-domains/connect-your-domain/#domain-configurations) for details.
 
 ## DNS records
 
@@ -43,4 +63,4 @@ For more details about using DNS records within Cloudflare, refer to [Manage DNS
 
 DNSSEC stands for DNS Security Extensions. It increases security by adding cryptographic signatures to DNS records. These signatures can then be checked to verify that a record came from the correct DNS server, preventing anyone else from issuing false DNS records on your behalf and redirecting traffic intended for your domain. You can read more about it in the [article about DNS security](https://www.cloudflare.com/learning/dns/dns-security/).
 
-For help setting up DNSSEC in Cloudflare, refer to [Enable DNSSEC](/dns/dnssec/).
+For help setting up DNSSEC in Cloudflare, refer to [Enable DNSSEC](/dns/dnssec/).

src/content/docs/dns/get-started.mdx

@@ -2,7 +2,7 @@
 title: Get started
 pcx_content_type: navigation
 sidebar:
-  order: 2
+  order: 1
 head:
   - tag: title
     content: Get started with Cloudflare DNS
@@ -11,7 +11,7 @@ head:
 
 import { GlossaryDefinition, Render } from "~/components";
 
-You can use Cloudflare DNS with a variety of [setups](/dns/zone-setups/).
+You can use Cloudflare DNS with a variety of [setups](/dns/zone-setups/). For an overview of what these setups are and if you are not yet familiar with specific DNS terminology, refer to [Concepts](/dns/concepts/).
 
 In the most common setup (full), you [add your domain](/fundamentals/setup/manage-domains/add-site/), import your [DNS records](/dns/manage-dns-records/), and [update your nameservers](/dns/nameservers/update-nameservers/) to make Cloudflare your primary authoritative DNS provider. Once the setup is completed:
 
@@ -33,8 +33,6 @@ The following links introduce important concepts and will guide you through acti
 
 - [How Cloudflare works](/fundamentals/concepts/how-cloudflare-works/): An overview of how Cloudflare works as a DNS provider and as a reverse proxy.
 
-- [DNS concepts](/dns/concepts/): Fundamental concepts to help you understand DNS terminology.
-
 - [DNS analytics](/dns/additional-options/analytics/): An overview of the different data sources and insights you can get when using Cloudflare DNS.
 
 - [Troubleshooting](/dns/troubleshooting/): A full resources list for when something is not working.

src/content/docs/dns/zone-setups/index.mdx

@@ -1,9 +1,8 @@
 ---
 pcx_content_type: concept
-title: Zone setups
+title: DNS setups
 sidebar:
   order: 3
-
 ---
 
 import { Details } from "~/components"
@@ -40,7 +39,7 @@ If you are on a Free or Pro plan, [full setup](/dns/zone-setups/full-setup/) is
 
 If you are on a Business or Enterprise plan, you can use [partial (CNAME) setup](/dns/zone-setups/partial-setup/) to keep your primary DNS provider and only proxy individual subdomains through Cloudflare.
 
-If you are on an Enterprise plan, you also have the option to use [zone transfers](/dns/zone-setups/zone-transfers/) to set up Cloudflare as either a primary or a secondary DNS provider. 
+If you are on an Enterprise plan, you also have the option to use [zone transfers](/dns/zone-setups/zone-transfers/) to set up Cloudflare as either a primary or a secondary DNS provider.
 </Details>