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What is DNS?
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- Skip2 Networks
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- Content Manager
DNS
What is DNS?
The Domain Name System (DNS) serves as the internet's phonebook, translating human-readable domain names like "google.com" into machine-readable IP addresses like "172.217.164.110" that computers use to locate and communicate with each other. Without DNS, users would need to memorize complex numerical IP addresses to visit websites, making the internet virtually unusable for everyday purposes. DNS operates through a hierarchical system of servers distributed globally, from root servers at the top level down to authoritative name servers that hold specific domain information, creating a robust and scalable infrastructure that handles billions of queries daily.
The DNS resolution process involves multiple steps and server types working together seamlessly. When you type a website address into your browser, your device first checks its local cache, then queries a recursive DNS resolver (often provided by your ISP or services like Cloudflare or Google). If the resolver doesn't have the answer cached, it systematically queries root servers, top-level domain servers, and finally authoritative name servers until it finds the correct IP address. This distributed approach ensures redundancy, improves performance through caching, and allows the system to scale globally while maintaining reliability even when individual servers experience issues.
DNS Resolution Example
When a user in Chicago types "shop.example.com" into their browser, their computer first checks if it already knows the IP address. Finding no cached result, it contacts their ISP's DNS resolver at 8.8.8.8. The resolver queries a root server, which directs it to the .com top-level domain server. The .com server points to example.com's authoritative name server, which finally responds with the IP address 203.0.113.45. The entire process typically completes in under 100 milliseconds, and the result is cached at multiple levels to make future requests even faster.
DNS Record Types
| Record Type | Purpose | Example |
|---|---|---|
| A | Maps domain to IPv4 address | example.com → 192.0.2.1 |
| AAAA | Maps domain to IPv6 address | example.com → 2001:db8::1 |
| CNAME | Creates domain alias | www.example.com → example.com |
| MX | Specifies mail servers | example.com → mail.example.com |
| TXT | Stores text information | SPF, DKIM, verification records |
| NS | Identifies authoritative name servers | example.com → ns1.provider.com |
DNS and CDN Integration
- Geographic Routing - Direct users to nearest CDN edge servers
- Load Distribution - Balance traffic across multiple server locations
- Failover Protection - Automatically route around failed servers
- Performance Optimization - Reduce latency through intelligent routing
- Traffic Management - Handle traffic spikes and DDoS mitigation
DNS Performance Factors
- TTL Settings - Control how long records are cached
- Server Response Time - Affects overall page load speeds
- Propagation Delays - Time for changes to spread globally
- Resolver Quality - Some DNS providers offer faster, more reliable service