@fifthson
Understanding DNS: More Than Just “Name to IP”
https://hackmd.io/@manbankat/H1A1XCo4bx
As part of my 2026 system design deep dive, I just completed a full breakdown of Domain Name System (DNS) architecture and it’s impressive how much complexity sits behind a single browser request.
DNS is one of those systems that “just works” until it doesn’t.
From a system design perspective, DNS is:
- A globally distributed system
- Hierarchical by design
- Highly available and fault-tolerant
- Latency-sensitive and cache-driven
I studied how a request flows through:
- Recursive resolvers (with caching & TTL trade-offs)
- Root name servers
- TLD servers (.com, .org, .io, etc.)
- Authoritative name servers (source of truth)
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