1. Suppose I acquire a VPS or establish a server at my residence and install a DNS server on it. This DNS server has an entry for the site1.com domain. When I enter site1.com in my browser, how will the request reach my DNS server? Additionally, how will others know about the new DNS server on the network?



2. Is it possible to find public DNS servers that can handle domains with multiple IP addresses and have a failover feature? Or is setting up a personalized DNS server necessary to accomplish this?

The key is not the emergence of a new DNS server, but rather that of a new domain.
Creating your own DNS and starting a new domain on it won't automatically make it known to others.

To make it known, the domain must be registered with a registrar who adds an entry to the corresponding domain's NS server. Keep in mind that your local DNS server has no impact on the .com zone and will only affect computers where it is configured by the DNS server.

In order to gain a better understanding of how DNS services work, I suggest reading up on it.

When you register your DNS, it is done in the root DNS servers which are uniform in nature. Most paid services have the capability to file and round-robin within the DNS. This includes services such as Amazon's Route53.

It's important to understand the process of registering a DNS and its integration with the root DNS servers. Additionally, having knowledge of the various features of paid DNS services can help you make informed decisions when selecting one for your business needs.

To delegate domains to a DNS server or the domain itself, you can follow these steps:

- For instance, if your server is ns1.site.com, you can create an alias (or second physical server) named ns2.site.com and delegate the domain from the registrar example.com on ns1.site.com and ns2.site.com.
- This ensures that all requests for *.example.com will be directed to your server. Keep in mind that it may take some time for these changes to take effect (usually 1-2 hours for the .com domain).

If you want to have the domain site.com for yourself, delegate the domain with this setup:
ns1.site.com 127.0.0.1
ns2.site.com 127.0.0.2
Remember to specify the real IP addresses of these servers or servers, but always use two entries.

The functioning of DNS servers can be understood by following the step-by-step process of how applications that respond to DNS queries function. When a user sends a request, the browser sends it to the network's DNS server, which then searches for a match of the domain name and IP address. If found, the site page loads immediately, if not, the request is sent to higher-level servers until a match is found. A response is then sent to the browser, and the page opens. The reverse procedure is also possible.

The foundation of domain name requests is the root servers that manage the root DNS zone. There are 123 root servers located in various parts of the world, managed by different operators. Resource records are required to store all matches of the domain and its IP addresses in a file on the DNS server in the DNS zone.

Several types of resource records exist, including A, MX, CNAME, NS, TXT, SPF, and SOA. After registering a domain, registering resource records is necessary to grant access to information about the domain for the rest of the servers. DNS servers should be registered in pairs to ensure reliability.

DNS servers are at risk from hacker attacks, which can cause numerous failures on the World Wide Web. In the past, social networks have been particularly affected by such attacks.

1. When you acquire a VPS or set up a server at home to run your DNS server, you need to ensure that it's publicly accessible. This means that your server should have a static public IP address if you want it to be a reliable DNS server. When someone enters site1.com in their browser, their computer queries a DNS resolver to resolve that domain name into an IP address. If your DNS server is running as authoritative for site1.com, you will need to configure your domain's nameservers with the registrar where you purchased the domain to point to your DNS server. This means you will need to register your server's IP address as the nameserver for site1.com.

Once your DNS server's IP is configured in the registrar's settings, any request for site1.com from anywhere on the internet will first hit the resolver (usually operated by an ISP or a third-party service) which, upon realizing it doesn't have the answer, will query your DNS server for the necessary information. Thus, to summarize, others would know about your DNS server based on the nameserver entries you set at the domain registrar, and requests will reach your DNS server once this configuration is complete.

2. Regarding public DNS servers that can handle multiple IP addresses and offer failover features, it's indeed possible to find such services. Many public DNS services and providers like Google Cloud DNS, Amazon Route 53, or Cloudflare offer advanced DNS management features that allow for load balancing, failover, and multiple A records pointing to different IP addresses. These services can automatically reroute traffic to a backup IP if the primary one goes down, which is a critical feature for high availability.

However, while utilizing a public DNS provider can solve the need for redundancy and failover without needing to set up your own server, a personalized DNS server offers more control over settings like custom records and specific configurations that might be necessary for certain applications. If your primary goal is high availability and you want to minimize the chance of downtime due to server issues, using a dedicated DNS service with these features would be advisable. Setting up your own DNS server, while advantageous for control and privacy, typically requires additional effort to implement similar failover strategies effectively.

Depending on the requirements of your project and your capability to manage a personalized system, both options exist to achieve your DNS needs effectively.