DNS in Detail | TryHackMe [Write-up]

Room can be found here https://tryhackme.com/room/dnsindetail

Note: For informative purposes, I have also included excerpts and infographics from the room.

Task 1: What is DNS?

DNS (Domain Name System) provides a simple way for us to communicate with devices on the internet without remembering complex numbers.

What does DNS stand for?

Domain Name System

Task 2: Domain Hierarchy

  • TLD (Top-Level Domain):
    1.gTLD (Generic Top Level)
    2. ccTLD (Country Code Top Level Domain)
  • Second-Level Domain
  • Subdomain

What is the maximum length of a subdomain?

63

Which of the following characters cannot be used in a subdomain ( 3 b _ – )?

_

What is the maximum length of a domain name?

253

What type of TLD is .co.uk?

ccTLD

Task 3: Record Types

DNS isn’t just for IP addresses. Various types of DNS records exist.

The most common ones:

A RecordResolve to IPv4 addresses
AAAA RecordResolve to IPv6 addresses
CNAME RecordResolve to another domain name, for example, TryHackMe’s online shop has the subdomain name store.tryhackme.com which returns a CNAME record shops.shopify.com.
MX RecordResolve to the address of the servers that handle the email for the domain you are querying
TXT RecordFree text fields, multiple uses, for example to list servers that have the authority to send an email on behalf of the domain or to verify ownership of the domain name when signing up for third party services

What type of record would be used to advise where to send email?

MX

What type of record handles IPv6 addresses?

AAAA

Task 4: Making a Request

What happens when you make a request

What field specifies how long a DNS record should be cached for?

TTL

What type of DNS Server is usually provided by your ISP?

Recursive

What type of server holds all the records for a domain?

Authoritative

Task 5: Practical

What is the CNAME of shop.website.thm?

nslookup –type=CNAME shop.website.thm

What is the value of the TXT record of website.thm?

nslookup –type=TXT website.thm

What is the numerical priority value for the MX record?

nslookup –type=MX website.thm

What is the IP address for the A record of www.website.thm?

nslookup –type=A website.thm