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What is a DNS Server?

What is a DNS Server? A DNS (Domain Name System) server is a critical component of the internet that enables the translation of human-readable domain names into IP addresses. It acts as a phonebook for the internet, helping devices and computers find the correct website or service when a user types in a URL or clicks on a link.

Without DNS servers, users would have to remember complex numerical IP addresses for every website they want to visit, making the internet much less user-friendly. Instead, DNS servers take care of the behind-the-scenes translation and ensure that users can easily access the web.

DNS servers maintain a database of domain names and their corresponding IP addresses. When a user requests access to a website, the DNS server looks up the IP address associated with the domain name and directs the user’s device to the correct location.

Related Read: What is a DNS NS Record? 

Types of DNS Services

The most common types of DNS servers are:

Recursive DNS Server

A recursive DNS server is a type of DNS server that receives DNS queries from clients and then resolves them by forwarding them to another DNS server or server.

Authoritative DNS Server

An authoritative nameserver contains the definitive answer for a particular domain name. An authoritative name server can be configured to provide answers to queries different than what it receives from its upstream resolver.

Related Read: What is a DNS Record? | 8 Main Types of DNS Records 

Purpose of a DNS Server

A DNS (Domain Name System) server serves a vital purpose in the functioning of the internet. It acts as a database and directory, translating human-readable domain names into IP addresses so that users can easily access websites and online services. 

The main purpose of a DNS server is to enable users to access the web by typing in a simple and memorable domain name instead of having to remember complex numerical IP addresses.

In addition to enabling easy access to websites, DNS servers also help to distribute the load of incoming traffic, ensure redundancy and reliability, and protect against cyber threats. They maintain a database of domain names and their corresponding IP addresses and direct users to the correct location when a request is made.

In short, the purpose of a DNS server is to act as a bridge between human-readable domain names and technical IP addresses, making the internet more user-friendly and efficient for users worldwide.

Working of a DNS Server

Putting in a URL is the same as telling your computer to look up a certain IP address and establish a connection. 

To accomplish this, it makes use of the Domain Name System (DNS) server, which consists of several interconnected servers:

  • DNS recursive resolver
  • Root name servers
  • TLD nameservers
  • Authoritative nameservers

Here’s a general overview of how a DNS server works:

  • Domain Name Resolution: The first step in the DNS process is to resolve a domain name into its corresponding IP address. This is done by a client, such as a web browser or email client, when it needs to access a website or send an email.
  • Client Query: The client sends a query to its local DNS resolver, asking for the IP address of the domain it wants to access.
  • Local DNS Resolver: The local DNS resolver is responsible for checking its cache to see if it already has the information for the requested domain. If it does, it returns the IP address to the client.
  • Recursive Query: If the local DNS resolver does not have the information in its cache, it sends a recursive query to a root DNS server.
  • Root DNS Server: The root DNS server responds to the recursive query with a referral to the top-level domain (TLD) DNS server responsible for the TLD of the requested domain.
  • TLD DNS Server: The TLD DNS server responds to the query by referring to the authoritative DNS server responsible for the specific domain.
  • Authoritative DNS Server: The authoritative DNS server is responsible for maintaining the records for the specific domain. It responds to the query with the IP address of the domain.
  • Client Cache: The client cache stores the IP address of the domain it has looked up. The next time the client needs to access the same domain, it can use the cached IP address instead of going through the entire DNS process again.
  • Client Connects to Website: Finally, the client uses the IP address to connect to the website or server it wants to access, and the process is complete.

Failure of DNS Servers

Several potential causes of DNS server failure include loss of power, malicious hacking attempts, and hardware failure. When the Internet was young, problems with DNS servers might have serious consequences. 

Now, DNS has a lot of built-in redundancy, which is a huge relief. Most Internet service providers (ISPs) offer redundant recursive resolvers for their customers, and there are many copies of the root DNS servers and TLD nameservers. (Personal computer users may also employ public DNS resolvers such as Cloudflare’s 1.1.1.1.) Popular websites typically have many copies of their authoritative nameservers.

Some users may experience delays in the event of a big DNS server failure due to the volume of requests being handled by backup servers. Still, only a massive DNS outage would render a significant chunk of the Internet inaccessible. 

In 2016, when one of the largest DDoS attacks in history hit the DNS provider Dyn, this was a real occurrence. When you sign up for Cloudflare’s Managed DNS Service, you’ll also get DNS security measures designed to keep your server safe from assaults and other typical threats.

DNS Lookup vs. DNS Resolver

DNS lookup is a query to an authoritative name server for the IP address of a domain. On the other hand, the DNS resolver is software that implements the Domain Name System protocol and translates domain names into IP addresses.

The DNS protocol is currently based on TCP/IP and UDP/IP. The client sends a request to a name server via UDP or TCP. The server responds with an answer within seconds and can be used in any application that needs it.

The DNS resolver is responsible for translating human-readable URLs into numerical IP addresses that computers can understand. This service has many applications, including email delivery and web browsing.

The main difference between DNS lookup and DNS resolver is that while you can use the latter to find out whether a domain exists or not (as well as its IP address), you cannot use it to find out what type of information is hosted at that domain (for instance, if it’s an FTP server).

Final Words

What is a DNS server, you ask? It’s the backbone of the internet that allows us to access websites with ease. Simply put, a DNS (Domain Name System) server acts as the internet’s phonebook, translating domain names into IP addresses. Essentially, it’s a crucial part of the infrastructure that makes accessing online resources as simple as typing a word.

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Which Type of DNS Record Identifies an Email Server?

The DNS record that identifies an email server is the Mail Exchange (MX) record. MX records specify which email server is responsible for accepting email messages on behalf of a particular domain name. When someone sends an email message to a domain, the sender’s email server looks up the MX record for that domain to determine where to send the message.

The MX record specifies the hostname of the email server and a priority value. The priority value indicates the order in which email servers should be tried in case the primary server is unavailable.

What is an Email Server?

An email server is a computer system used for sending and receiving emails. When an email is sent, it undergoes a series of servers to reach the intended recipient. An email server software must be installed on your computer system so that it performs as a mail server. The software helps the system administrator in managing and creating email accounts for the respected domain hosted on the server.

The primary purpose of an email server is to collect and distribute emails to the final destination. It can also encrypt emails to ensure a secure transfer of data. Emails are integral to corporate communication and the number of global email users is expected to grow to 4.6 billion by 2025. However, this also gives an increased surface area to malicious actors to attempt phishing and spamming, making it important for IT-driven companies to invest in DMARC services and use encryption.

Types of Email Servers

An email server can be perceived as an online post office where emails are exchanged within and without a network. Let’s know its types to learn which types of DNS record identifies an email server. 

SMTP Servers

SMTP is short for Simple Mail Transfer Protocol, an email server protocol managing outgoing email requests and sending emails. Without it, an email can’t be sent.

POP3 Servers

POP3 is short for Post Office Protocol 3, a commonly used protocol used for receiving email messages over a secure network connection. It’s a single-way protocol where emails are received and held on the email server. The number ‘3’  refers to the third version of the original POP protocol.

IMAP

IMAP stands for Internet Message Access Protocol, a server used to keep copies of messages on the email server. It basically allows users to access emails wherever, whenever, and from whichever device. 

What is a DNS Server?

A DNS server is just like a phonebook where domain names and their corresponding IP addresses are stored. So, when you type a domain name like ‘amazon.com,’ the DNS server is responsible to find the corresponding IP address to the site you want to visit. This is because it’s easier for humans to remember domain names instead of numerical IP addresses like 123.45.678. 

DNS servers run dedicated programs to communicate with each other using special protocols. So, when you enter a domain name in the address bar, the DNS server will send a DNS query to various servers, each of which translates to a different part of the domain name you entered.

Types of DNS Servers

There are three types of DNS servers- primary servers, secondary servers, and caching servers.

Primary Servers

The primary DNS server is the authoritative server of the zone where tasks like creating subdomains are performed. Apart from this, alterations related to the zone or modifications or additions to RRs in the zone files should be performed using the primary server only. 

Generally, there’s only one primary server for any given zone, except when you integrate AD services and a Microsoft DNS server.

The primary DNS server usually has its own IP address that’s used by client computers to send queries while resolving a domain name into an IP address. It may behave as a secondary DNS server if several domains are hosted on the same computer.

Secondary Servers

Secondary DNS servers are backup servers hosted by your domain registrar. The guidelines are already set to allow them to handle DNS requests. It’s used to retrieve DNS records where the main server isn’t available or fails to perform its function. 

They also help to automatically update information from the primary server so that you don’t have to do it manually when there are any changes in your infrastructure.

Caching Servers

Caching servers behave as an extra layer of backup for primary and secondary servers. However, these are complicated and time-taking to configure.

What is a DNS Record?

A DNS record is a set of instructions loaded on a DNS server that tells about a domain and its corresponding IP address. These instructions are important for the process of DNS lookup. All domains must have at least a few vital DNS records so that users can access their website using a domain name. Apart from this, there are a few optional record types too. 

Which Type of DNS Record Identifies an Email Server?

Let’s dive into the main topic- which type of DNS record identifies an email server. 

MX Record

A DNS MX record or Mail Exchange record is required for matching emails to the intended recipient’s address. It defines which mail servers are assigned to accept incoming mail for a specific domain. It also tells the route for the emails sent to that domain. You may experience failure in email delivery if it isn’t configured correctly. 

DNS records and how they help identify email servers

When you send an email to someone, you probably don’t give much thought to the journey that email takes before it arrives in the recipient’s inbox. But there are actually a lot of behind-the-scenes processes that happen to make sure your email is delivered to the right place.

One of the most important components of email delivery is the Domain Name System (DNS). DNS is a system that translates domain names (like google.com or yahoo.com) into IP addresses (like 172.217.0.46 or 98.137.246.8). Without DNS, it would be much more difficult to connect to websites or send emails.

In addition to translating domain names to IP addresses, DNS also stores various types of records that provide additional information about a domain name. One of the most important types of DNS records for email delivery is the Mail Exchange (MX) record.

An MX record is a type of DNS record that specifies which email server(s) are responsible for accepting incoming email messages for a particular domain name. When someone sends an email to a recipient at a specific domain name (like [email protected]), their email server uses DNS to look up the MX record for example.com. The MX record will typically include the hostname of the email server(s) responsible for handling email for that domain.

Here’s an example of what an MX record might look like:

Breaking down the MX record

  • example.com. is the domain name that this MX record applies to.
  • IN is the record class, which is usually “IN” for Internet.
  • MX is the record type, indicating that this is an MX record.
  • 10 is the priority value, indicating the order in which email servers should be tried. A lower value means a higher priority.
  • mail.example.com. is the hostname of the email server responsible for handling incoming email for example.com.

In this example, any incoming email messages for example.com will be directed to the email server at mail.example.com. If the mail server at that hostname is unavailable, the sender’s email server will attempt to send the message to the next MX record with a higher priority value.

MX records can be configured with multiple email servers to provide redundancy and ensure that email messages are delivered even if one server is down or unavailable. It’s also possible to set up backup MX records with higher priority values, so that if the primary email server is unavailable, the backup server(s) will accept incoming email until the primary server is back online.

Overall, MX records are a critical part of email delivery and help ensure that your messages are delivered to the right place. By specifying the hostname of the email server(s) responsible for handling incoming email, MX records help make sure that your email messages reach their intended recipients.

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