Basic yet pertinent information behind the workings of DNS and linux configuration.

linux_dns_basics.txt

Author: Aaron Phalen | Twitter: @aaron_phalen | Email: [email protected]

Summary:
  The domain name system (DNS) it useful in translating ip-address to domain names and vice-versa.
  Below will describe the basic workings of DNS and will show configuration on a linux server.

A. DNS and BIND
   1. DNS - Domain Name Sytem
     a) Translates between ip addresses and hostname                          
   2. BIND - Berkely Internet Name System
     b) DNS for linux
        
B. Bind Linux Packages 
   1. bind
   2. bind-utils
   3. redhat-config-bind

C. The Domain Name Space
   1. Domain Name Space (.com, .edu, .gov, etc..)
   2. Domain Names (buyzdirect.com, osu.edu, etc..)
   3. Subdomains  (blog.buyzdirect.com, etc..)
 
   Note: The domain name space of the internet can be tought of as a tree
   structure similar to that of the linux file system.
   
D. Concepts
   1. Each domain in the domain name space has a node, which is an node 
      in the aforementioned tree analogy
   2. Each node has a resource record (RR) that stores facts about the domain
   3. Nodes can have an numerous children, aka - subdomains
   4. root is called .
   Note: resolution sequence: root --> domain name space --> domain --> resource record (RR) - Ip Address
   
D. Domain Name Resoltution
  1. There are 13 root domain name servers around the world that handoff request to other name server
  2. Handoff process will continue until authoritative name server for domain is found
  3. One name server and multiple slave name servers for each domain 
    a) the slaves serve the same date as the master but purpose is to distribute server load 

E. Configuration Files
  1. /etc/nsswitch.conf
    a) system host information
  2. /etc/hosts
    a) computers on network
  3. /etc/network/interfaces
    a)network interace devices
      i) lo --> localhost
      ii) eth0 --> public network 
  3. /etc/resolv.conf
    a) ip addresses of known domain names
  4. /etc/hostnames
    a) ip addresses
    b) domain names
    c) aliases
  Note: sudo ifdown && sudo ifup --> need to reset networking to flush and re-configure network config settings.