What is DNS?

DNS (Domain Name System) is the address book of the internet. It translates domain names that people can remember (like google.com) into IP addresses that computers use (like 142.250.185.3). Without DNS, you would have to remember the numeric IP address for every website, which is practically impossible.

When you visit a website, you type a recognizable name in your browser. In the background, your computer asks DNS servers: "What is the IP address of this domain name?" DNS answers, and your browser can then connect to the right server. This happens automatically and usually takes a few milliseconds.

DNS is fundamental to how the internet works. It makes the web user-friendly and flexible. Website owners can switch servers without visitors noticing - only the DNS record is changed to point to the new IP address.

How does DNS work?

The DNS process starts when you type a URL in your browser. Your computer (the "client") sends a DNS query to a DNS resolver - usually your internet provider's DNS server or a public DNS service like Google DNS (8.8.8.8) or Cloudflare (1.1.1.1).

If the resolver has cached the answer from a previous query, it immediately returns the IP address. This is fast - a few milliseconds. If not, a recursive lookup process begins where multiple DNS servers are queried.

The resolver first asks the root nameservers. There are 13 root server clusters worldwide that form the starting point of the DNS system. These servers don't know what google.com is, but they do know which servers are responsible for .com domains.

Next, the resolver asks the TLD nameserver (Top Level Domain). For google.com, this is the .com nameserver. This also doesn't know the exact IP address but does know which nameservers are responsible for google.com specifically.

Finally, the resolver asks the authoritative nameserver of the domain. This is the server that has the definitive information about google.com. It returns the IP address, along with other DNS records like MX records (for email) and TXT records (for verification).

The answer is cached by the resolver for a certain time (the TTL - Time To Live). If the same question comes again within that time, the answer can come directly from cache without repeating the whole process.

Different types of DNS records

A records (Address records) are the most basic. They link a domain name to an IPv4 address. For example: example.com A 192.0.2.1 means example.com points to IP 192.0.2.1.

AAAA records are the IPv6 variant. They link domain names to IPv6 addresses (the new generation IP addresses that are longer). Many websites have both A and AAAA records for maximum compatibility.

CNAME records (Canonical Name) create aliases. You can, for example, set www.example.com CNAME example.com, so www.example.com points to the same IP as example.com. This is more convenient than configuring duplicate A records.

MX records (Mail Exchange) determine which mail servers are responsible for email for your domain. Without correctly configured MX records, you can't receive email at addresses with your domain.

TXT records contain text information. They're used for domain verification (e.g., for Google), SPF records for email security, and DKIM keys for email authentication.

NS records (Name Server) specify which nameservers are authoritative for a domain. These are the servers that have the definitive information about your domain.

Advantages of DNS

User-friendliness is the biggest advantage. People remember names better than numbers. "google.com" is easier to remember than "142.250.185.3". This makes the internet accessible to everyone.

Flexibility for administrators is crucial. You can move your website to a new server by simply adjusting the DNS record. Visitors notice nothing - they still use the same URL.

Load balancing becomes possible via DNS. A domain can point to multiple IP addresses. DNS can distribute traffic across different servers, increasing scalability and reliability.

Geographic targeting is possible with GeoDNS. Different visitors from different countries can be sent to different servers. An American gets an American IP address, a Dutch person a Dutch IP address - for faster performance.

Email routing via MX records separates web hosting from email hosting. Your website can be with provider A while your email is with provider B. This gives freedom in your choices.

Subdomains make organization simple. blog.example.com can point to a different server than shop.example.com. Each part of your online infrastructure can be managed independently.

Disadvantages and problems with DNS

Propagation time can be frustrating. When you change DNS records, it can take 24-48 hours before the change is visible worldwide. This is due to caching at different DNS servers. During this period, some visitors may see the old server, others the new one.

DNS failures mean complete downtime. If your DNS servers are offline, no one can find your website, even if the web server runs perfectly. This makes DNS a single point of failure.

Security risks like DNS spoofing and cache poisoning are real. Attackers can spread false DNS information, causing visitors to be sent to malicious servers instead of your real website.

Privacy concerns come into play. By default, DNS queries are not encrypted. Your internet provider (and potentially others) can see which websites you visit by monitoring your DNS queries. This is why DNS over HTTPS (DoH) and DNS over TLS (DoT) were developed.

Complexity increases with advanced setups. GeoDNS, failover configurations, and advanced routing require technical knowledge. Errors in DNS configuration can lead to downtime or suboptimal performance.

TTL dilemma: short TTLs mean quick updates but more DNS queries (and load on nameservers). Long TTLs reduce load but make updates slower. You have to find a balance.

Who needs DNS knowledge?

Website owners must understand basic DNS. You need to know how to link your domain to your hosting, how to set up email, and what to do with problems. This is fundamental knowledge for anyone with a website.

Developers deploying applications must be able to configure DNS. Setting up subdomains for staging environments, configuring SSL certificates (which require domain validation), or setting up API endpoints - everything requires DNS knowledge.

IT administrators and system administrators work with DNS daily. From troubleshooting connectivity issues to setting up internal DNS for corporate networks - DNS is a core competency.

Marketing teams using third-party tools encounter DNS with domain verification. Google Search Console, Facebook Business Manager, email marketing platforms - all require DNS record modifications.

E-commerce owners must understand MX, SPF, and DKIM records for reliable email delivery. Transactional emails (order confirmations, password resets) must arrive, and correct DNS is essential for this.

Anyone buying a domain needs basic DNS knowledge to connect the domain to hosting, email, and other services.

Practical tips for DNS management

Use reliable DNS providers. Your domain registrar often offers DNS, but dedicated DNS providers like Cloudflare, Route 53 (AWS), or Azure DNS offer better performance, uptime, and features. Free options like Cloudflare are excellent.

Set low TTLs for planned changes. If you know you're migrating soon, lower your TTL several days in advance to 300 seconds (5 minutes). After migration, raise it again. This minimizes propagation time.

Test DNS changes before implementing them. Tools like DNSChecker.org show how your DNS records look worldwide. Use nslookup or dig commands to verify records.

Implement DNS redundancy with multiple nameservers. Most providers automatically offer multiple nameservers. Check that you have at least two - preferably geographically distributed.

Monitor your DNS health. Services like UptimeRobot or Pingdom can monitor your DNS responses and alert you to problems. You want to know your DNS is down before customers start complaining.

Document your DNS records. Keep track of what each record does. If you have to come back in a year, you don't want to have to guess why a certain TXT record is there.

Secure your DNS with DNSSEC where possible. This is a security extension that prevents false DNS responses. Not all providers support this, but it significantly increases security.

Use separate accounts for DNS and hosting. If your hosting account is compromised, you don't want attackers to also be able to change your DNS. Separation of concerns increases security.

Consider DNS failover for critical websites. Some DNS providers detect when your primary server is offline and automatically point to a backup server. This minimizes downtime.

Understand your registrar vs DNS provider difference. Your domain registrar is where you buy the domain. Your DNS provider hosts the nameservers. These can be the same, but don't have to be. You can buy your domain at GoDaddy but use Cloudflare DNS.

Learn basic troubleshooting commands. nslookup example.com, dig example.com, and ping example.com are essential tools to diagnose DNS problems. Invest time in learning how these work.

Be careful with transfers between providers. Domain transfers can reset DNS settings. Take screenshots of your current DNS records before transferring, so you can restore everything if something goes wrong.

Compare DNS providers on speed, reliability, and features. Not all DNS is equal - some providers have faster response times, better uptime, or advanced features like GeoDNS. Check reviews and do speed tests.

Frequently Asked Questions

How much does web hosting cost on average?

Web hosting costs between €3 and €15 per month for shared hosting on average. VPS hosting starts around €10-€20 per month, and dedicated servers from €50 per month.

Can I upgrade to a different package later?

Yes, with most hosting providers you can easily upgrade to a larger package when your website grows. This can usually be done without downtime.

Is Dutch hosting better than foreign hosting?

For Dutch visitors, Dutch hosting is often faster due to the shorter distance. Additionally, communication with support is easier and you comply with GDPR legislation.