Overview
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Design
Architecture vs Design
Design Challenges
Design Goals
Concepts
Standards Based Design
Data Standards
Design Patterns
Clinical Serialization Standards
Security Standards
Serialization Standards
Terminology Standards
Transport Standards
Stereographic Projection
Event-Driven Design
Cultural-Dependent Design
Service Interface Design
Contract-Based Design
Distributed Transaction Design
Testability Design
Code Generation Design
Science of Great User Experiences
Visual Design
Glossary

DNS

Dynamic Name Service, a network service that can resolve Domain Names to current IP Addresses.

In order to prevent a DNS Server to be hit for each and every request, a Domain Name is typically resolved once using a DNS Server, and the result is then Cached. For how long depends on the record’s TTL.

There are a few different types of records, each of which have different meanings, among which:

A, returns a IPv4 address.
AAAA, returns an IPv6 address.
CNAME, points to another domain name (which results in a new DNS request for the name that is returned).
MX, for Email.
NS, to point to other DNS Servers.

Sources