WSA DFN50223 CH1

Structure of DNS

Definition of DNS

A service to resolve a hostname of IP address.

Based on a distributed hierarchical to resolve.

Structure of DNS

Top Level Domain Name (TLD)

Second Level Domain Name (SLD)

Root

Subdomains

Structure of DNS

Root domain is segmented using "." dot/period.

such as; .com,.edu, .gov, .net & etc.

In addition, the root domains are also organized via geographically, as the TLD for Malaysia is .my.

How DNS works

The pc or user enters a search in a domain like download.beta.example.com. to a local DNS server.

The Local server then cycles through servers by sending queries to the Root Server, TLD DNS Server, Authoritative DNS Servers looking to provide an answer to the user.

2 types of DNS Lookup

Iterative Queries: Direct mention answers, have/don't have.

Recursive Queries: Always gives an answer even if its incorrect.

DNS Lookup Process

Pc request internet to access a website

First server is a recursive resolver which is maybe provided by your Internet Service Provider (ISP)

Then the first server contacts the root server that are located globally that contains TLDs.

TLDs give DNS information to the first server.

When the first server receives the information, it will try to contact the domain and figure out the IP address.

Once IP address is found, the first server gives it to the computer's browser to access the web server content via newly accustomed IP address.

DNS Servers Roles

Forwarder

Authoritative Server

Conditional Forwarder

Caching-only server

Installing DNS with Active Directory

Install DNS Server role with Server Manager/PowerShell.

If the DNS server is for domain name services for Active Directory, then install on domain controller.

Windows detects if the server is configured as domain controller, if yes then integrates DNS zones with Active Directory.

DNS Zones

PRIMARY ZONES: with or without active directory (editable).

SECONDARY ZONES: backup servers (not editable)

STUB ZONES: Almost the same as Secondary, however, only consists of necessary data for when 2 companies merge (to provide information from both DNS servers) & protect DNS database. (not editable)