Welcome!

What is DNS

The main functions of DNS

Domain Name Format

The DNS Tree

Root Servers

TLD Servers

Authoritative Name Servers

Iterative Name Resolution

DNS Resolvers

Recursive Name Resolution

Local Name Resolution

Caching

DNS Name Resolution Workflow

Domain Name Registration Hierarchy

Choosing a TLD

Domain Name Registration Process

Choosing a Second-Level Domain

EPP Status Codes

Choosing a Registrar

Zones & Resource Records

SOA Record

A & AAAA Records

NS Record

PTR Record

CNAME Record

MX Record

TXT Record

Architecture

Configuring the Cache-Only DNS Server

Configuring the Client

Configuring DNS High Availability

Configuring the Authoritative DNS Server

RCODES

DNS Messages

The DNS Header

Constructing DNS Packets

Capturing & Analysing DNS Traffic

Troubleshooting Methodology

Troubleshooting DNS Configuration Issues

Troubleshooting DNS Latency Issues

DNS Query Flood Attack

NXDOMAIN Attack

Phantom Domain Attack

DNS Cache Poisoning Attack

Summary