RFC 1034 / START HERE
DNS, before the details
DNS: Domain Name System
DNS is the Internet's distributed naming system. It helps turn a name people can remember into information computers need, such as a server's network address.
The idea in one picture
You enter a domain name
DNS looks up its records
The app learns where to connect
A simplified picture of the idea; the chapters explain the actual mechanisms.
Why it exists
You should not need to memorize a numeric address for every website. DNS distributes the naming work across many independently managed servers.
A familiar example
You enter a website name. A resolver finds the relevant DNS information so your browser can locate the service.
Helpful background
You can start here without reading another RFC. If these ideas are unfamiliar, these short introductions may help.
What you’ll learn next
Begin with chapter one, or choose a topic.
- The name treeA DNS name locates a node in one shared tree. The rightmost labels are closest to the root.→
- Resource recordsDNS stores typed records, not simply a table of names and IP addresses.→
- Delegation & glueA parent zone points toward the servers responsible for a child. Address glue can make that referral reachable.→
- Iterative resolutionA resolver can do the chasing itself, choosing progressively closer servers until it finds an answer.→
- Recursive resolutionA stub client asks a recursive service to return the final answer or an error instead of forwarding referrals to the user.→
- Caches & TTLCaching reduces repeated work. A TTL limits how long learned data can be reused without another lookup.→
- AliasesAn alias redirects DNS resolution to a canonical name, where the desired record can be found.→
- Missing names & failuresA nonexistent name, a name without the requested type, and a temporary lookup failure communicate different things.→
- Wildcard synthesisDNS wildcards synthesize records under specific tree-matching rules; they do not replace every matching string.→
- Zone maintenanceAn authoritative secondary checks whether its zone copy has changed and retrieves a replacement when needed.→
- Reverse lookupsIPv4 reverse lookup uses an ordinary DNS question in the IN-ADDR.ARPA tree.→
- Transport & historical scopeRFC 1034 defines concepts. It depends on a companion implementation specification and later extensions for modern DNS.→
This introduction explains RFC 1034 (1987). Read the original RFC ↗