A DNS server is a computer on the internet that stores and distributes domain name information. When you type a web address into your browser, your device sends a request to a DNS server asking: "What IP address belongs to this domain name?" The DNS server looks up the answer and sends it back, allowing your browser to connect to the correct website.
DNS stands for Domain Name System. Without DNS servers, you would need to memorise long strings of numbers (IP addresses) instead of user-friendly names like google.com. Your internet service provider typically assigns you a default DNS server automatically, but you can change this in your device or router settings.
Common DNS servers include:
- Your ISP's DNS server (usually the default)
- Google Public DNS (8.8.8.8 and 8.8.4.4)
- Cloudflare DNS (1.1.1.1)
- OpenDNS and others
Why this matters: DNS server choice can affect your browsing speed, privacy, and security. Some DNS providers filter malicious sites, whilst others prioritise speed or privacy. If a DNS server is slow or down, websites may load slowly or become unreachable, even if your internet connection is fine.
Common gotchas include DNS caching, where outdated information lingers after you change servers, and DNS leaks on VPNs, where your queries might still reach your ISP's server instead of staying private. Changing your DNS is a straightforward troubleshooting step if websites load slowly or you experience connectivity issues.