DNS (Domain Name System)

  • Bridge the gap between humans and computers
    • Humans are better with names, computers are great with numbers
  • Resolves names --> numbers
    • https://google.com -->
  • Application Layer client-server system of computers and databases
  • Made up of:
    • Name space
      • Entire collection of computer names and their IPs
      • Stored in databases on DNS name servers around the globe
    • Name servers
      • Hold databases organized in hierarchical structure
    • Resolvers
      • DNS client that requests info from DNS name servers

Root Servers

  • Root of the DNS hierarchy
  • 13 sets of root servers around the world
    • Operated by 12 different organizations
    • Each set has their own unique IP address

TLD Server

  • Stores address information for top level domains (.com, .ca, etc.)

Authoritative Name Server

  • Responsible for knowing everything about the domain
  • Includes IP for the domain name

Domain Names

  • Character-based names are easier to remember
  • Last part of FQDN is called top-level domain (TLD)
  • Can be registered with Internet naming authority
    • Works on behalf of ICANN
    • Restricts what types of hosts can be associated with .arpa, .mil, .int, .edu, and .gov
  • Name resolution
    • Process of discovering IP address when you have the FQDN

Fully Qualified Domain Name

  • Fully qualified domain names
  • Unique character-based name

Computer Science Networking