What is DNS and How Does It Work - A Complete Guide

The internet can sometimes feel like a maze, with lots of confusing terms and concepts. One of these terms is DNS, short for Domain Name System. Even if you've heard of it, you might still wonder what it's all about. In this article, we'll explain DNS in simple terms—what it is and how it helps the internet work. We'll also talk about why DNS is essential for email marketing. So, let's dive in.

What is DNS (Domain Name System)?

DNS, which stands for Domain Name System, is like an extensive address book for the internet. Just like you use a phone book to find someone's phone number, DNS helps your computer find websites by matching their names (like google.com) to their actual locations on the internet (saved as IP addresses 172.217.7.174). So basically, DNS helps ensure you get to the right website when you type in a web address.

How does DNS work?

When you type a website address into your browser, like "facebook.com," your computer doesn't know where that website is located. So, it asks a special computer called a DNS server for help. The DNS server knows where all the websites are located, so it looks up the address for "facebook.com" and tells your computer where to find it. Then your computer can connect to the website and show it to you. It's like asking a friend for directions to a new place—you ask, they know, and they tell you how to get there!

There are 4 key DNS servers that work in the background to load a webpage:

• DNS Recursor: Acts like a librarian, fetching information for your browser.
• Root Nameserver: The first step where human-readable hostnames are translated into IP addresses.
• TLD Nameserver: A specific section of the library, like a rack of books. For example, in google.com, ‘.com’ is the TLD.
• Authoritative Nameserver: The final stop in the nameserver query, providing the right address for the website.

What happens when you search for a website?

When you search for a website, your request goes through a DNS lookup process. Here's how it works:

1. You type the website name (like 'example.com') into your browser.

2. Your request travels through the internet to a special computer called a DNS resolver.

3. The resolver starts looking for the website by asking for a DNS root server.

4. The root server tells the resolver which Top top-level domain (TLD) server to check (like .com or .net).

5. The resolver asks the TLD server for the IP address of the website's nameserver.

6. The TLD server gives back the IP address.

7. The resolver then asks the website's nameserver for the IP address of the website.

8. Finally, the resolver sends the IP address back to your browser. Once your browser has the IP address, it can request the webpage, and the server at that address sends it back to be displayed in your browser.

Cool, right? Who knew so much goes behind a simple web search?

So, the role of DNS is not limited to locating and fetching IP addresses based on a user query - it also stores a lot of information related to your domain - known as DNS records. These can largely be categorized into email authentication mechanisms like SPF, DKIM, DMARC (more on these later), MX records, and TXT records.

How many types of DNS records are there?

Here are some of the most common DNS records:

A Record (Address Mapping record)

The A Record is the address record commonly used to associate hostnames (like domains) with corresponding IPv4 addresses.

AAAA (IP version 6 Address record)

Similar to the A Record, the AAAA Record functions as an address record but for IPv6 addresses.

CNAME (Canonical Name record)

The CNAME record aliases one hostname to another. Essentially, it operates similarly to an A Record, but instead of linking to an IP address, it associates with another hostname.

MX (Mail Exchange record)

MX records are crucial for routing outgoing emails to an email server. They designate an SMTP email server for a domain, ensuring efficient email delivery.

TXT (Text record)

TXT records contain machine-readable data added to your DNS. They serve various purposes, including email security, where they can house records such as SPF, DKIM, and DMARC for enhancing email authentication and protection.

What is the importance of DNS in email marketing?

When you send an email, it's like sending a digital letter. But before that letter can reach its destination, your email address (what comes after the @ symbol) must be matched to a location on the internet—a bit like finding an address on a map. This is where DNS comes in handy. Just as it helps your browser find websites, it also helps mail servers find the right place to deliver your email.

Here’s why DNS setup and management is important in cold email marketing:

• Sender Authentication: DNS records like SPF (Sender Policy Framework), DKIM (DomainKeys Identified Mail), and DMARC (Domain-based Message Authentication, Reporting, and Conformance) can help authenticate your email’s identity.
• Email Deliverability: Proper DNS configuration, including SPF, DKIM, and DMARC records, can positively impact email deliverability. ISPs (Internet Service Providers) use these records to authenticate and route emails, increasing the chances of messages reaching recipients' inboxes instead of being flagged as spam.
• Reputation Management: DNS plays a role in managing your sender reputation - a must for email deliverability. DNS records help establish trust with ISPs and email providers, signaling that your domain is legitimate and trustworthy.
• Tracking and Analytics: DNS records like MX (Mail Exchange) records determine the mail servers responsible for receiving email on behalf of your domain. This infrastructure is essential for tracking email delivery, opens, clicks, and other engagement metrics, which are vital for assessing the effectiveness of email marketing campaigns.

To start with cold email outreach, you must set up your DNS server records and authenticate your email address. You must take care of three major authentications: SPF, DKIM, and DMARC.

Let’s discuss in detail what each term means and how to set them up in your DNS server.

How to set up SPF, DKIM, and DMARC?

What is SPF?

SPF is a mechanism that helps prevent email spoofing by specifying which IP addresses are authorized to send emails on behalf of a domain. It works by publishing a DNS record containing a list of authorized sending IP addresses for a domain. If the sending IP address matches the one listed in the SPF record, the email is more likely to be delivered successfully, as it helps mail servers distinguish legitimate emails from spam.

How to set up SPF record in the DNS server?

Before setting SPF, you can check the status of your current SPF record using a tool like MxToolbox. If it hasn’t been set yet, you can follow the steps below:

Important: The steps will slightly differ depending on the domain host. But the general flow has been explained below:

• Go to your domain provider. (eg. GoDaddy, Namecheap, etc.)
• Access your DNS records settings.
• Add a new DNS record. It should be a TXT Record.
• TXT Record:

Value/Host name: @

TXT record value: v=spf1 include:_spf.google.com ~all (when using Google apps to send all emails from your domain)

What is DKIM?

DKIM adds a digital signature to your outgoing emails, allowing recipients to verify the authenticity of the sender.

When an email is sent, the sender's mail server generates a unique signature based on the email's content and includes it in the email headers.

How to set up DKIM in the DNS record?

Configuring DKIM involves adding the public key information to your server's records, typically in the form of a TXT record. To set up DKIM on your server, the initial step is generating the public key, which usually requires accessing your email provider's admin console.

The specific procedures may vary depending on your email service provider. For instance, Google Apps email users should note that DKIM signatures are typically disabled by default and must be manually enabled in the Google Admin console.

Once you have the public key, insert the generated TXT record into the appropriate location within your DNS records.

What is DMARC?

DMARC builds upon SPF and DKIM to provide an additional layer of email authentication and protection against spoofing and phishing attacks.

So, it acts like a gatekeeper for your emails, ensuring they're authentic and trustworthy. It sets rules for what should happen to emails sent from your domain and what action to take if they don't meet those rules.

If an email fails both SPF and DKIM checks, it fails DMARC.

There are three possible DMARC policies:

• None: Collect data about email authentication failures without taking any action on the failed messages.
• Quarantine: This policy instructs email providers to treat emails that fail DMARC checks as suspicious and either deliver them to the recipient's spam or junk folder.
• Reject: This policy is the strictest and directs email providers to reject emails that fail DMARC authentication outright, preventing them from reaching the recipient's inbox.

How to set up DMARC in DNS records?

• Access your domain's DNS records through your domain provider.
• Add a DMARC DNS record as a TXT record.
• TXT Record:

Host/Name: _dmarc

TXT record value: v=DMARC1; p=none; rua=mailto:[your email address]

Monitor DMARC reports to track email authentication and identify potential issues.

If you’re using Google Workspace to send emails, here’s the complete guide to setting up SPF, DKIM, and DMARC.

Wrapping-up

Now that you know about DNS and how to set up DNS server records and why they're important - you can use this information to better manage your domains. And if you're just starting with cold emailing journey, knowing about DNS records and email security like SPF, DKIM, and DMARC can improve your domain's reputation and ensure that your emails get delivered.