DNS Guide: How Domain Name System Works

Every time someone visits a website, DNS is working behind the scenes to connect them to the right server. If you own a website or plan to set one up, understanding DNS helps you configure your domain correctly, fix problems faster, and make informed decisions about your hosting setup.

What Is DNS?

DNS stands for Domain Name System. It is the system that translates human-readable domain names (like mrsoft.pk) into IP addresses (like 192.0.2.1) that computers use to locate each other on the internet.

Without DNS, you would need to memorize the IP address of every website you want to visit. DNS acts as the internet's phonebook — you look up a name, and it gives you the number.

DNS is a distributed system. There is no single server that holds all domain records. Instead, thousands of DNS servers around the world work together to resolve domain names into IP addresses.

How DNS Works Step by Step

When you type a domain name into your browser, here is what happens:

1. Browser cache check — Your browser first checks if it already knows the IP address for that domain from a recent visit.
2. Operating system cache — If the browser does not have it, it asks your operating system, which maintains its own DNS cache.
3. Recursive resolver — If neither cache has the answer, the request goes to a recursive DNS resolver, usually operated by your ISP (like PTCL, Nayatel, or StormFiber in Pakistan).
4. Root nameservers — The resolver asks a root nameserver, which directs it to the correct top-level domain (TLD) server (e.g., the .com or .pk server).
5. TLD nameservers — The TLD server points the resolver to the authoritative nameservers for your specific domain.
6. Authoritative nameserver — This server holds the actual DNS records for your domain and returns the IP address.
7. Connection — The browser connects to that IP address and loads the website.

This entire process usually takes milliseconds. The result is cached at multiple levels so subsequent visits are even faster.

DNS Record Types Explained

DNS records are instructions stored on authoritative nameservers. Each record type serves a different purpose. Here are the ones you will encounter most often:

A Record

Maps a domain name to an IPv4 address. This is the most fundamental DNS record. For example, an A record for example.com might point to 192.0.2.1.

CNAME Record

Maps one domain name to another domain name (an alias). Commonly used to point www.example.com to example.com. You cannot use a CNAME on the root domain itself — only on subdomains.

MX Record

Specifies which mail servers handle email for your domain. If you use a service like Google Workspace or Zoho Mail, you need to set MX records to route email correctly. MX records include a priority number — lower numbers mean higher priority.

TXT Record

Holds text-based information. TXT records are used for domain verification (proving you own a domain to services like Google Search Console), SPF records (email authentication), and DKIM signatures.

NS Record

Specifies which nameservers are authoritative for your domain. When you change nameservers at your domain registrar, you are updating NS records. These determine which DNS provider manages your domain's other records.

Tip: When setting up a new website, the two records you will configure most often are A records (to point your domain to your server) and CNAME records (to handle the www subdomain).

Nameservers and How to Change Them

Nameservers are the DNS servers that hold your domain's records. When you buy hosting, your provider gives you nameserver addresses, such as:

• ns1.hostingprovider.com
• ns2.hostingprovider.com

To change nameservers:

1. Log in to your domain registrar (where you bought the domain).
2. Find the DNS or nameserver settings — this is usually under "Domain Management" or "DNS Settings."
3. Replace the existing nameservers with the ones provided by your hosting company.
4. Save the changes and wait for propagation.

If you bought your domain and hosting separately, changing nameservers is how you connect the two. If they are from the same company, this is usually done automatically.

DNS Propagation

DNS propagation is the time it takes for DNS changes to spread across the internet. When you update a DNS record or change nameservers, the new information needs to reach DNS servers worldwide.

Propagation can take anywhere from a few minutes to 48 hours. The main factor is the TTL (Time to Live) value on your DNS records. TTL tells DNS servers how long to cache a record before checking for updates.

• Low TTL (300 seconds / 5 minutes) — Changes propagate faster because caches expire sooner. Useful before planned DNS changes.
• High TTL (86400 seconds / 24 hours) — Changes take longer to propagate but reduce DNS lookup load. Good for stable records that rarely change.

Tip: If you are planning to change your hosting provider, lower your TTL to 300 seconds a day or two before making the switch. This way, the DNS change will propagate faster when you update your records.

You can check propagation status using free online tools like whatsmydns.net, which shows whether DNS servers in different countries have received your updated records.

Common DNS Issues and Fixes

Here are the most frequent DNS problems website owners run into:

Website Not Loading After Nameserver Change

This is usually a propagation issue. Wait up to 48 hours. If the site still does not load after that, verify that you entered the correct nameservers — even a small typo will prevent resolution.

Email Not Working

If email stops working after a DNS change, check your MX records. They may have been reset or overwritten. Re-add the MX records specified by your email provider.

DNS_PROBE_FINISHED_NXDOMAIN Error

This error means the domain cannot be resolved. Possible causes: the domain expired, nameservers are not set, or DNS records are missing. Check your domain's registration status and DNS configuration.

Wrong Website Showing

If your domain shows a different website or a parking page, your A record may be pointing to the wrong IP address. Update it with the correct IP from your hosting provider.

Tip: Before contacting support, try clearing your browser cache and flushing your local DNS cache. On Windows, run ipconfig /flushdns in Command Prompt. This eliminates stale cached records as a cause.

DNS Considerations for Pakistani Users

DNS works the same way everywhere, but there are a few things Pakistani website owners should keep in mind:

ISP DNS Resolvers

Pakistani ISPs like PTCL, Nayatel, and StormFiber operate their own DNS resolvers. These sometimes cache records longer than expected, which can make propagation appear slower locally. If you have changed your DNS and the change is visible globally but not on your connection, try switching to a public DNS resolver like Google DNS (8.8.8.8) or Cloudflare DNS (1.1.1.1) in your device's network settings.

.pk Domain DNS

If you have a .pk domain registered through PKNIC, you manage nameservers through PKNIC's portal. The interface is straightforward — log in, select your domain, and update the nameserver fields. The same DNS principles apply to .pk domains as to .com or any other TLD.

Using Cloudflare for DNS Management

Many Pakistani website owners use Cloudflare as their DNS provider, even if their hosting is elsewhere. Cloudflare offers a free plan that includes DNS management, and their global network of servers can improve DNS resolution speed for your visitors. To use Cloudflare, you change your domain's nameservers to the ones Cloudflare assigns you, then manage all your DNS records through the Cloudflare dashboard.

Understanding DNS gives you control over where your domain points and how your website and email services connect. For more about connecting domains to hosting, read our domain vs hosting guide. If you are setting up a new site, our SSL guide covers the next step — securing your site with HTTPS.