DNS Resolution Simulator
Learn how DNS works with an interactive step-by-step simulator. Visualize the DNS hierarchy, understand caching at different levels, and see the difference between recursive and iterative queries.
Category: Networking
Topics covered: dns, networking, educational, interactive, infrastructure
// simulator
DNS Resolution Simulator
Learn how DNS works with an interactive step-by-step simulator. Visualize the DNS hierarchy, understand caching at different levels, and see the difference between recursive and iterative queries.
Watch step-by-step how your browser resolves domain names to IP addresses
A example.com💡 Key Takeaways
- DNS is hierarchical: Your query travels through multiple levels (browser → OS → resolver → root → TLD → authoritative).
- Caching speeds things up: Each level can cache results. A cache hit avoids the full lookup chain.
- TTL controls freshness: Records expire after their TTL. Lower TTL = fresher data, but more lookups.
Understanding DNS Resolution
DNS Hierarchy
- Root Servers (.): The top of the DNS hierarchy. 13 root server clusters worldwide direct queries to TLD servers.
- TLD Servers (.com, .org): Manage top-level domains and point to authoritative nameservers.
- Authoritative Servers: Hold the actual DNS records for specific domains.
- Recursive Resolvers: Your ISP or DNS provider (like 1.1.1.1 or 8.8.8.8) that does the lookup work.
DNS Record Types
- A Record: Maps domain to IPv4 address (e.g., 192.168.1.1).
- AAAA Record: Maps domain to IPv6 address (e.g., 2001:db8::1).
- CNAME Record: Alias pointing to another domain name.
- MX Record: Mail server for the domain.
Key concepts
- TTL (Time To Live): How long a DNS record can be cached before needing refresh.
- Recursive query: The resolver does all the work and returns the final answer.
- Iterative query: Each server returns a referral; the client follows the chain.
- DNS caching: Happens at browser, OS, and resolver levels to speed up lookups.
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