DNS Resolution Simulator - Learn How Domain Name System Works
DNS Resolution Simulator
Watch step-by-step how your browser resolves domain names to IP addresses
Domain
Record Type
Query:
A example.comDNS Resolution Path
Browser
OS Cache
DNS Resolver
Root Server
TLD Server
Auth Server
💡 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: Resolver does all the work and returns final answer
- • Iterative Query: Each server returns a referral, client follows the chain
- • DNS Caching: Happens at browser, OS, and resolver levels to speed up lookups