Domain & DNS

Basics

Route 53

• Domain registration
• DNS routing
• Health checking

Domain transfer

Pre-requisites

• Unlock the domain
• Disable Domain Privacy
• Ensure registrant valid email address
• Get the EPP code (Extensible Provisioning Protocol) which the authorization/transfer code provided by your current registrar when transferring a domain name to a different registrar

DNS record types

Record	Description
A	IPv4 Address record
AAAA	IPv6 Address record
CNAME	Canonical Name record
MX	Mail Exchanger record
NS	Nameserver record
PTR	Pointer record
SOA	Start Of Authority record
SRV	Service Location record
TXT	Text record

Windows hosts file

C:\Windows\System32\drivers\etc\

Linux

Local

cat >> /etc/hosts

Network

cat /etc/resolv.conf

Local resolution overrides the DNS server
–> can be changed in /etc/nsswitch.conf

Tools

https://www.whatsmydns.net/

https://mxtoolbox.com/

nslookup & dig

Nslookup queries internet domain name servers in two modes:

• Interactive: nslookup + enter

nslookup
> set type=ns
> google.com

• Non-interactive: single query

nslookup google.com

-type=ns		Name Server records.
-type=soa		Start of Authority records
-type=a		A address records
-type=any		All available records
-type=mx		Mail Exchange server information
-type=ptr		Pointer records (reverse DNS lookups)
-type=hinfo		hardware-related information about the host
-debug		info useful for debugging

Install on Ubuntu/Debian

sudo apt install dnsutils

Install on Red Hat/CentOS

nslookup is part of the bind-utils package

sudo yum install bind-utils

dig

dig (linux) allows you to query information about various DNS records