Hardware & Software Components of the web

Networks

• Links two or more computers• Share Resources• Increases productivity• Mostly plug and play today

Hardware Overview

• Hardware is the physical, tangible parts of a Computer system.

Primary Network Components

• Servers• Clients / Workstations• Resources

• Every network requires two or more of these items connected

Basic Roles

Routers

• Originally to connect multiple networks• For Example, the internal network (office) and the external network (www)

• Today they perform more than one function• Often include Wireless Access Points• Allows multiple computers to have access to the Internet• Adds a level of security• Have built in Firewalls

Firewalls

• Software or hardware solution.• Blocks unsolicited network traffic.• Configured by administrator to control incoming and outgoing

transmissions according to organizational policies

Servers• Core component – critical• Centralise control of resources• Centralise security• Simplifies administration• Several critical roles• File servers• Print servers• Authentication• Remote access• Email

• Multipurpose and single purpose

Servers

• Dedicated• Specific applications or services• Fewer resources• Improved network performance• For example - Web server

• Nondedicated• One or more services• Perform administrative actions• Front end for administrator• Can also act as a workstation

• Networks today commonly have a combination of the two

DMZ – De Militarised Zone

Mail Server

Mail Servers

• Two Types• Out Going

• SMTP = Simple Mail Transfer Protocol• Incoming

• POP3 = Post Office Protocol• IMAP = Internet Message Access Protocol

Sending an Email

• After composing a message and hitting send, your email client connects to your domain's SMTP server.• Your email client communicates with the SMTP server, giving it your email

address, the recipient's email address, the message body and any attachments.• The SMTP server processes the recipient's email address - especially its domain. If

the domain name is the same as the sender's, the message is routed directly over to the domain's POP3 or IMAP server - no routing between servers is needed. If the domain is different, though, the SMTP server will have to communicate with the other domain's server.

Sending an Email• In order to find the recipient's server, the sender's SMTP server has to

communicate with the DNS, or Domain Name Server. The DNS takes the recipient's email domain name and translates it into an IP address. The sender's SMTP server cannot route an email properly with a domain name alone; an IP address is a unique number that is assigned to every computer that is connected to the Internet. By knowing this information, an outgoing mail server can perform its work more efficiently.• Now that the SMTP server has the recipient's IP address, it can connect to its

SMTP server. This isn't usually done directly, though; instead, the message is routed along a series of unrelated SMTP servers until it arrives at its destination.• The recipient's SMTP server scans the incoming message. If it recognizes the

domain and the user name, it forwards the message along to the domain's POP3 or IMAP server. From there, it is placed in a sendmail queue until the recipient's email client allows it to be downloaded. At that point, the message can be read by the recipient.

Web Software - CMS• CMS - Content Management System• an application that is used to manage web content• Collaborative - allows multiple contributors to create, edit and publish. • Allows users create, manage, and modify content on a website without the

need for specialised technical knowledge• No need to understand the underlying code (HTML, CSS, or Javascript)• Allows web creator to focus on content• WYSIWYG – What you see is what you get• Content is stored in a database• Content is displayed in a presentation layer based on a template• The interface is browser-based meaning it can be accessed from many devices

Web Software - CMS• Basic features of a CMS:• Content creation (allows users to easily create and format content)• Content storage (stores content in one place, in a consistent fashion)• Workflow management (assigns privileges and responsibilities based on roles

such as authors, editors and admins)• Publishing (organizes and pushes content live)

Web Software - CMS• CMS Examples• Wordpress (Approx 35% of websites use this. 65% of CMS websites use WP)

• Whitehouse.gov• Mercedes Benz• Pempo

• Joomla – (Approx 2.5% of all websites, 5% of CMS Websites) • Nasa.gov• Better defined roles for editing than Wordpress

• Drupal – High security, used by UK Government, Police etc.• Hardest to get up and running

• Many, many others

• From https://kinsta.com/blog/wordpress-vs-drupal/

Wordpress

• Change Themes – how the website looks• 53,000+ free plugins, plus thousands of more premium plugins.

• Plugins – Allow specific functionality to be on the website• 5,000+ free themes, plus thousands of more premium themes.• Warning! – Most Wordpress security compromises are through rogue or

compromised plugins

• WordPress normally the default tool for creating a website• It’s user-friendly and easy for non-developers to add functionality.• You can quickly create an attractive and functional website.• It’s easy to find both free and professional help.

Web Server

• Specialised Software - listens for requests and responds accordingly• HTML, CSS, and Javascript files stored on webserver, displayed in browser• Uses HTTP• Always running & Always connected to the web

Web Server types

• Static - a computer (hardware) with an HTTP server (software). The server sends its hosted files "as-is" to your browser.

• Dynamic - a static web server plus extra software, most commonly an application server and a database. The application server updates the hosted files before sending them to your browser via the HTTP server.• For example, Wikipedia has thousands of webpages, but they are not real HTML documents!

They use a few HTML templates and a giant database with the content

Web Authoring Software

• A type of desktop publishing tool allowing users to do web coding through a graphical user interface• The program that generates the required HTML, CSS, and JavaScript.• Users can switch between the rendered pages and the code• Alternative to hand coding the pages• Some Examples:

• Corel Website Creator• WebSite X5 Evo• HTML-Kit• Komodo IDE• BlueFish• Adobe Dreamweaver

Databases• A collection of structured information or data• Managed by a DBMS – Database Management System

• Interface between data and the user

• Data is stored in rows and columns called tables • A Table is like a single Excel Spreadsheet

• Tables make processing and data querying efficient.• Databases hold large (enormous) collections of organized information• Allows multiple users simultaneous access• The data is easily accessed, managed, modified, updated, controlled, and

organized. • Most databases use structured query language (SQL) for writing and querying

data.