DNS

No matter where it connects to the internet, everything that connects has an IP address. DNS, or Domain Name System, is a global network that translates web site names into numerical addresses needed to navigate directly to them.

Browsing the web would not be possible without this invisible network that serves as a universal phonebook, making it possible to visit websites within seconds of searching a keyword or phrase.

What Is DNS?

DNS stands for Domain Name System, which works behind-the-scenes to connect website names you type into your browser with their corresponding IP addresses, to their corresponding domain names online. DNS serves as an essential piece of infrastructure that connects billions of people and over 300 million domain names online.  Its success might seem miraculous, but is in fact an amazing engineering achievement!

Everything connected to the internet has an Internet Protocol (IP) address. The domain name system translates this string of numbers into human-readable website names that you type into your web browser, seamlessly and instantly! No one notices it happening!

Instead of keeping all the IP addresses and domain name mappings together in one central repository, DNS utilizes a network of servers to share this information. There remains one definitive root name server known as the authoritative name server.  However, many others provide localized services.

When typing a domain name into your browser, your computer first checks its local DNS cache for answers. If it finds them it will send them back directly. Otherwise, it queries a recursive DNS server provided by either your Internet service provider or IT team.  These servers act like librarians that search their own database before asking another DNS server to locate records if necessary.

Each server contains records that indicate how to resolve DNS queries, such as an A record for website hosting IP addresses, or CNAME records that point an alias domain name back to another website. DNS administrators manage these records using software called domain name system management tool.

DNS also supports an additional security measure known as DNSSEC that adds cryptographic signatures to data stored in DNS records, helping prevent hackers from forging domain and website identities and creating fake domain names and websites.

DNS Server

A DNS Server is a computer network system which maps human-readable domain names to Internet Protocol (IP) addresses used by web servers for displaying websites. This translation takes place behind-the-scenes and remains completely undetectable by end users.

An average Internet connection utilizes numerous DNS servers distributed worldwide to synchronize directory information and ensure redundancy. The mapping between IP addresses and domain names is integral for web browsing, email correspondence, instant messaging services, and other online activities that utilize the Internet.

The DNS service operates according to rules and principles established by the Internet Engineering Task Force’s Request for Comments 1035 document, RFC 1035. At its core, its most basic function is storing records about top-level domains (TLD), second-level domain names (SLD), third-level domains (TDN), SMTP mail exchangers (MX) and pointers for reverse DNS lookups (PTR), as well as pointers for reverse DNS lookups (PTR).

When you type a website name into your browser, your operating system initiates a query with its local DNS resolver, who uses its cache to check whether it already contains that information.  If not, they send it with a recursive flag to another DNS server outside their local network that could answer it.

This final server, similar to a librarian that locates books you need in its library, responds to queries with an IP address for the site you need. Recursive searches end either with success or an error message notifying that its name can’t be found.

DNS queries can take an inordinately long time to execute. To speed them up, many DNS servers will cache results of previous inquiries to reduce bandwidth consumption and CPU utilization costs.

DNS caching can be vulnerable to attacks. A malicious actor could insert corrupt data into a resolving device’s cache, which would lead it to provide inaccurate results when requested for specific domains.  This process is known as DNS Cache Poisoning.

How Does A DNS Server Work?

When computer users type a domain name into their browsers, a query is sent to DNS servers asking which network or IP address is the owner of the name. In response, they send users directly to the appropriate website without them even realizing it happened.  Behind the scenes however, various processes occur within DNS to complete its lookup and provide answers.

The process starts by searching on a DNS resolver/recursive server known as a resolver/recursive server. This first server that receives queries could either have the information stored within its cache, or will conduct multiple queries to narrow down where to find it.  Think of this like searching a library collection to find exactly the book that fits!

Recursive servers begin by querying root nameservers and TLD nameservers for information related to your query. These serve as indexes pointing towards book racks where books may be located. Once this step has been taken, when necessary the information found will then be passed along to an authoritative domain nameserver.  This particular server will have all of this knowledge about a domain, and has its own copy of a phone book, something recursive servers do not do.

If the authoritative server has the information, they will return it to the recursive server and cache it for future queries, helping ensure users receive fast access. In addition, these servers may send back replies containing their IP addresses for future reference.

Once information has been retrieved, recursive servers send it directly to a user’s browser for display on its webpage. Although this seems complicated at first, this process happens very quickly and is undetectable  by most users.

What Is A Domain Name?

Domain names are unique identifiers of internet resources, such as names using human language. When typing one into your web browser,  a DNS network looks up the IP address associated with that domain and connects your device directly with it, helping people discover websites, as well as sharing them.

When selecting your domain, be sure that it relates directly to your business and stands out as memorable for visitors. Shorter domains are generally easier for audiences to recall and may help them reach your site more quickly, providing them with an improved user experience overall.

Your domain registration options vary, depending on which registration service best meets your needs and needs, but the general process involves visiting an appropriate registration service and entering your desired name into their search bar. When your desired name becomes available for purchase, just follow the instructions on that page to complete your purchase and register it.

Every domain that wants to join the domain name system must abide by the rules and procedures laid out by DNS protocol, which outlines what can and cannot be included in domain names. 

Each domain offers its own set of characters to use when creating its name, with optional extensions available to further differentiate it. A maximum domain length can reach 63 characters while one character suffix can also be included to distinguish itself.

The domain name system serves as the internet equivalent of a phone book, with domain name servers acting as its connections. Accurate records with faster response times were necessary in order to keep all this information in one centralized place, so domain name servers were created in order to distribute this data effectively and maintain accurate records worldwide.

IP Address

So, what exactly is an IP address? IP stands for Internet Protocol, and an IP address is a unique numerical label assigned to each device connected to a computer network. It serves as an identifier, allowing devices to communicate with each other over the internet. Think of it as a virtual address that enables data packets to be sent and received accurately.

There are two primary types of IP addresses: IPv4 and IPv6. IPv4, which stands for Internet Protocol version 4, is the most widely used addressing system. It consists of four sets of numbers, separated by periods, with each set ranging from 0 to 255 (e.g., 192.168.0.1). However, the continuous growth of internet-connected devices has led to the depletion of available IPv4 addresses.

To address this issue, IPv6, or Internet Protocol version 6, was introduced. IPv6 uses a hexadecimal system and offers a significantly larger pool of addresses compared to IPv4. Its addresses are represented by eight sets of four hexadecimal digits, separated by colons (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). IPv6 adoption is gradually increasing to accommodate the expanding internet landscape.

When you connect to the internet, your device receives an IP address from your Internet Service Provider (ISP). This address allows you to send and receive data across the network. Whenever you visit a website, send an email, or stream a video, your IP address is used to route the data packets to the appropriate destination.  The DNS server is involved as outlined earlier.

IP addresses also play a crucial role in network security. They help identify the source and destination of internet traffic, allowing network administrators to monitor and control access to their networks. Additionally, IP addresses are used for geolocation targeting, enabling websites and online services to provide region-specific content and services. 

CNAME

CNAME records are shorthand records in DNS that link one hostname to another. They make it possible to direct domain aliases to the same server as their parent domain instead of having each alias have its own IP address.  This enables webmasters to change only one record at once if their server needs changing IP addresses.

Content delivery networks (CDNs) use CNAME records for content delivery by adding their address as a CNAME record to an origin server hosting your website, meaning anyone accessing resources on that origin server are automatically redirected to the CDN where they can receive an optimized version of your website.

When using a CNAME record, browsers that request content will receive a DNS lookup response that points them towards the canonical domain name (known as the root domain ) associated with that hostname and uses its IP address as part of its connection process with that host to retrieve and display its contents.

DNS CNAME records serve a number of applications, with their most frequent purpose being mapping an alias to the canonical domain for websites. This ensures users can always locate and connect with them. Furthermore, using CNAME records ensures any URL redirections implemented comply with Domain-based Message Authentication Reporting and Conformance (DMARC).

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