Delve into software architecture, exploring key principles, patterns, and quality attributes. Gain insights with case studies and projects, enhancing your practical skills in system design and optimization.

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This course offers a deep dive into the world of software architecture. It’s designed to equip software developers and architects with the knowledge and skills necessary to create, evaluate, and optimize software systems. The course covers a range of critical topics to ensure a strong foundation in architectural principles and strategies.

You will start by exploring architectural concepts and the relationship between quality attributes, requirements, and architectural styles. You’ll also examine different architectural patterns and strategies, including centralized and decentralized architecture, layered pattern, broker pattern, and microservices. Then, you’ll go into the details of important quality attributes needed while developing an architecture.

The course is equipped with multiple case studies and two projects to further enhance learning. These real-world scenarios and hands-on projects are strategically incorporated to give learners practical insights.

Software Architecture in Applications

# Overview
**Domain name servers (DNS)** are key components of the internet that translate human-readable domain names (such as "google.com") into numerical IP addresses that computers use to interact with one another.

 
# How DNS works
When a user enters a domain name or clicks a hyperlink, the browser sends a request to a DNS server to resolve the domain name to an IP address. The DNS server searches its database for the domain name and delivers the appropriate IP address to the browser. The IP address is then used by the browser to connect to the server that hosts the website or service associated with the domain name.



 
# DNS records
DNS servers keep a database of DNS records, which contain information on domain names and the IP addresses associated with them. DNS records are classified into numerous kinds, including:

 
+ **A records:** These map domain names to IP addresses. For example, the A record for "google.com" maps the domain name to the IP address of the server that's hosting the website.

+ **AAAA records:** Quad A (AAAA) records map a domain name to an IPv6 address. These records are used in the same way as A records, but for IPv6 addresses. 

+ **CNAME records:** Canonical name (CNAME) records allow multiple domain names to be mapped to the same IP address. For example, the CNAME record for "www.google.com" could map the domain name to the same IP address as the record for the "google.com" domain name.
 
+ **MX records:** Mail exchange (MX) records map domain names to the servers that handle email for the domain. For example, the MX record for "google.com" would map the domain name to the servers that are responsible for handling email for the domain.
 
+ **NS records:** Name server (NS) records identify the DNS servers that are responsible for a particular domain. For example, the NS record for "google.com" would identify the DNS servers that are responsible for resolving domain names for the "google.com" domain.

+ **TXT records:** Text (TXT) records allow domain owners to associate text data with a domain. These records are used for various purposes, such as verifying domain ownership, storing Sender Policy Framework (SPF) information, and storing spam-fighting information.

+ **SRV records:** Service (SRV) records are used to specify the location of a service, such as a Session Initiation Protocol (SIP) or XMPP server, for a domain.

+ **PTR records:** Pointer (PTR) records map an IP address to a domain name. These records are used for reverse DNS lookups, which are used to determine the hostname associated with a particular IP address.
 
# DNS resolvers
**DNS resolvers** are client-side programs or services that are responsible for sending DNS queries to DNS servers and receiving responses. When a user's computer or device wants to resolve a domain name, it sends a query to a DNS resolver, which forwards it to a DNS server. The DNS server searches its database for the domain name and returns the appropriate IP address to the DNS resolver, which transmits the IP address back to the user. 



Get an overview of domain name servers (DNS) and DNS load balancing, as well as its types.

Getting Started

The Architecture Meta-Frame

Architectural Styles and Strategies

Architectural Styles and Strategies

Scalability

Availability

Load Balancing

A Basic Load Balancer

Security

Caching

Web Architecture

Case Studies

A Basic MVC Data Flow

Conclusion

Domain Name Servers

Overview

How DNS works

DNS records