📖 IT Bible

DNS

Domain Name System - a global and highly distributed network service that resolves strings of letters into IP addresses for you

  • converts domain names into IP addresses

Domain Name - something that can be resolved by DNS

Name Resolution - process of using DNS to turn a domain name into an IP address is known as name resolution

5 Primary Types of DNS Servers:

  1. Caching name servers - purpose is to store known domain name lookups for a certain amount of time
  2. Recursive name servers - performs full DNS resolution requests
  3. Root name servers - there are 13 root servers
  4. TLD name servers - see below
  5. Authoritative name servers - responsible for the last 2 parts of any domain name

All domain names in the global DNS system have a TTL, or Time to Live TTL (Time to Live) - a value, in seconds, that can be configured by the owner of a domain name for how long a name server is allowed to cache an entry before it should discard it and perform a full resolution

Anycast - a technique that’s used to route traffic to different destinations depending on factors like location, congestion or link health

TLD (Top-level domain) - represents the top of the hierarchical DNS name resolution system

  • the last part of any domain name Pasted image 20260615213405