Back to the basics: Introduction to DNS

Copy right@A Layman

For me, problems like network DNS, database, or network are hard to be solved. Especially in a large project, you may have several CDNs, load balancers, firewalls, or redundant policy like SQL server always on. They don’t matter with the code but configuration.

The border between developers and operators become closed today. So we need DevOps who know how to develop and also know the operation and IT knowledge.

I decided to back to the basics and enhance these bits of knowledge. I also expect that this article can help someone who also wants to learn from the basics.

This article will mention about:

• Anatomy of a domain name
• The name resolve process of DNS
• DNS query types
• DNS lookup is normally based on UDP
• Public DNS server
• Internal name resolve process on a Windows computer
• Forwarding, Reversing, and Resource Record (RR)

Anatomy of a domain name

1. Top-level domain/First-level domain

• The last part of a domain name (e.g., .com , .net, .edu , etc)
• TLDs are handled by a non-profit organization known as ICANN