# IT Fundamentals/Internet

This lesson introduces Internet services and web browsers.

## Objectives and Skills

Objectives and skills for the Internet portion of IT Fundamentals certification include:
* Compare and contrast common Internet service types.
** Fiber optic
** Cable
** DSL
** Wireless
*** Radio frequency
*** Satellite
*** Cellular
* Given a scenario, configure and use web browsers.
** Caching/clearing cache
** Deactivate client-side scripting
** Browser add-ons/extensions
*** Add
*** Remove
*** Enable/disable
** Private browsing
** Proxy settings
** Certificates
*** Valid
*** Invalid
** Popup blockers
** Script blockers
** Compatible browser for application(s)
* Explain basic networking concepts.
** Basics of network communication
*** Basics of packet transmission
*** DNS
**** URL-to-IP translation
*** LAN vs. WAN
** Basic protocols
*** HTTP/S
*** POP3
*** IMAP
*** SMTP

## Readings

* Wikipedia: Internet access
* Wikipedia: Web browser
* Wikipedia: Internet protocol suite
* Wikipedia: Domain Name System

## Multimedia

* YouTube: Common Internet Service Types
* YouTube: Configure & Use Web Browsers

## Activities

* Research plans available from different wired (fiber optic, cable, DSL) and wireless (radio frequency, satellite, cellular) Internet providers. Compare mobility, availability, bandwidth, reliability, delay, concurrent connections, security, and cost. How is speed measured for these services (bps, Kbps, Mbps, Gbps, or Tbps)?
* Research email protocols. Identify the differences between HTTPS, POP3, IMAP, and SMTP. Note what each protocol does and when each should be used. Check settings in your preferred email program to determine which email protocols you are using.
* Complete the GCF Global: Internet Safety tutorials.
* Configure and use web browsers. Try two or three different web browsers (Chrome, Firefox, Edge, Safari, etc.) for each of the following activities.
** View cache contents and then clear the cache.
** Disable JavaScript and test website functionality. Reenable JavaScript when you finish testing.
** Check installed browser extensions (add-ons). Install Privacy Badger to experiment with if you don't currently have any extensions installed. Practice enabling and disabling extensions. Remove any extensions you don't recall installing or don't use anymore.
** Test private browsing. Research what actual privacy private browsing provides and what privacy it doesn't or can't address.
* View and test web site certificates.
** Review GlobalSign: How to View SSL Certificate Details in Each Browser and What You Can Learn. Compare SSL certificates for the GlobalSign page and this Wikiversity page.
** Visit BadSSL.com and test your browser's response to different certificate errors.
* Use a protocol analyzer to view the basics of packet transmission and URL-to-IP translation:
** Review Wireshark and the lessons on how to:
*** Install Wireshark
*** Start a Wireshark Capture
*** Stop a Wireshark Capture
*** Capture Network Traffic
*** Filter Displayed Traffic
** Start a Wireshark capture and then use a browser to navigate to a website you haven't visited recently (within the last day or so).
** Stop the Wireshark capture.
** Filter for DNS traffic and observe how the DNS protocol was used to translate the URL's fully-qualified domain name (FQDN) into an IP address.
* Use a protocol analyzer to compare HTTP and HTTPS traffic:
** Start a Wireshark capture and then use a browser to navigate to a website using HTTP, and another website using HTTPS.
** Stop the Wireshark capture.
** Filter for HTTP traffic and observe that the contents of the traffic are visible in the capture.
** Filter for HTTPS traffic and observe that the contents of the traffic are encrypted and not visible in the capture.

## Lesson Summary
### Internet Service

* An Internet service provider (ISP) is an organization that provides services for accessing, using, or participating in the Internet.
* Wired Internet access options include analog and digital computer modems attached to telephone lines, coaxial television cable (CATV), and fiber optic cables.
* Wireless Internet access options include Wi-Fi, cellular, and satellite connections.
* Optical fiber is a flexible, transparent fiber used most often as a means to transmit light between the two ends of the fiber and permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables.
* Cable Internet is a form of broadband Internet access which uses the same coaxial cable infrastructure as cable television.
* Digital subscriber line (DSL) is a family of technologies that are used to transmit digital data over telephone lines.
* Wireless communication is the electromagnetic transfer of information between two or more points that are not connected by an electrical conductor.
* The frequencies of the radio spectrum that are available for use for communication are treated as a public resource and are regulated by government organizations. These regulations determine which frequency ranges can be used for what purpose and by whom.
* Wi-Fi technology may be used to provide local network and Internet access to devices that are within range of one or more routers that are connected to the Internet.
* The Wi-Fi coverage of one or more interconnected access points (hotspots) can extend from an area as small as a few rooms to as large as many square kilometers.
* Satellite Internet access is Internet access provided through communications satellites.
* Mobile Internet refers to access to the internet via a cellular telephone service provider.

### Web Browsers

* A web browser (commonly referred to as a browser) is a software application for retrieving, presenting and traversing information resources on the World Wide Web.
* The primary purpose of a web browser is to bring information resources to the user, allowing them to view the information, and then access other linked information.
* A browser cache is used for temporary storage of web documents, such as HTML pages and images, to reduce bandwidth usage, server load, and perceived lag.
* Client-side scripting, typically using JavaScript, changes interface behaviors within a specific web page in response to mouse or keyboard actions, or at specified timing events.
* A browser extension is a plug-in that extends the functionality of a web browser.
* Browser extensions are used for improving a browser's user interface, security or accessibility, blocking advertisements, and various other features to make browsing the internet easier and more pleasant.
* Browser extensions have access to everything done by the browser, and can do things like inject ads into web pages, or make "background" HTTP requests to third-party servers. As a result, a malicious browser extension may take action against the interest of the user that installed it.
* Private browsing is a feature in some web browsers where the browser creates a temporary session that is isolated from the browser's main session and user data. Browsing history is not saved, and local data associated with the session, such as cookies, are cleared when the session is closed. These modes are designed primarily to prevent data and history associated with a particular browsing session from persisting on the device, or being discovered by another user of the same device. Private browsing modes do not necessarily protect users from being tracked by other websites or their Internet service provider (ISP).
* A proxy server is a server application or appliance that acts as an intermediary for requests from clients seeking resources from servers that provide those resources.
* A public key certificate, also known as a digital certificate or identity certificate, is an electronic document used to prove the ownership of a public key. The certificate includes information about the key, information about the identity of its owner (called the subject), and the digital signature of an entity that has verified the certificate's contents (called the issuer). If the signature is valid, and the software examining the certificate trusts the issuer, then it can use that key to communicate securely with the certificate's subject.
* Web development and design technologies allow an author to associate any item on a pop-up with any action, including with a cancel or innocent looking button. All major web browsers let users block unwanted pop-ups almost completely.
* Script blockers block active (executable) web content, which a user can wholly or partially unblock by whitelisting a site or domain from the browser or browser extension's toolbar menu.
* Cross-browser compatibility is the ability of a website or web application to function across different browsers and degrade gracefully when browser features are absent or lacking.

### Networking Concepts

* The Internet protocol suite provides end-to-end data communication specifying how data should be packetized, addressed, transmitted, routed, and received. This functionality is organized into four abstraction layers, which classify all related protocols according to the scope of networking involved. From lowest to highest, the layers are the link layer, containing communication methods for data that remains within a single network segment (link); the internet layer, providing internetworking between independent networks; the transport layer, handling host-to-host communication; and the application layer, providing process-to-process data exchange for applications.
* Common link-layer protocols include Ethernet, Wi-Fi, and DSL.
* The standard internet layer protocol is IP.
* The standard transport layer protocols are TCP and UDP.
* Common application layer protocols include:
** HTTP and HTTPS (web)
** POP3, IMAP, and SMTP (email)
** FTP, FTPS, and SFTP (file transfer)
** SNMP (network monitoring)
* Packets are transmitted by switches and access points on local networks and by routers between networks.
* The Domain Name System (DNS) is a hierarchical and decentralized naming system for computers, services, or other resources connected to the Internet or a private network. It associates various information with domain names assigned to each of the participating entities. Most prominently, it translates more readily memorized domain names to the numerical IP addresses needed for locating and identifying computer services and devices with the underlying network protocols.
* A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building.
* A wide area network (WAN) is a telecommunications network that extends over a large geographical area for the primary purpose of computer networking, often established with leased telecommunication circuits.

## Key Terms
### CSS (Cascading Style Sheets)

    A style sheet language used for describing the presentation of a document written in a markup language.

### DSL (Digital Subscriber Line)

    A family of technologies that are used to transmit digital data over telephone lines.

### FTP (File Transfer Protocol)

    A standard network protocol used for the transfer of computer files between a client and server on a computer network.

### FTPS (File Transfer Protocol over Secure Sockets Layer)

    An extension to the commonly used File Transfer Protocol (FTP) that adds support for the Transport Layer Security (TLS) and the (now prohibited) Secure Sockets Layer (SSL) cryptographic protocols.

### HTML (Hypertext Markup Language)

    The standard markup language for documents designed to be displayed in a web browser.

### HTTP (Hypertext Transfer Protocol)

    An application protocol for distributed, collaborative, hypermedia information systems used as the foundation of data communication for the World Wide Web.

### HTTPS (Hypertext Transfer Protocol Secure)

    An extension of the Hypertext Transfer Protocol (HTTP) used for secure communication encrypted using Transport Layer Security (TLS).

### IMAP (Internet Mail Access Protocol)

    An Internet standard protocol used by e-mail clients to retrieve e-mail messages from a mail server.

### IP (Internet Protocol)

    The principal communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.

### ISP (Internet Service Provider)

    An organization that provides services for accessing, using, or participating in the Internet.

### POP (Post Office Protocol)

    An application-layer Internet standard protocol used by local e-mail clients to retrieve e-mail from a remote server over a TCP/IP connection.

### POP3 (Post Office Protocol 3)

    The current version of the Post Office Protocol (POP).

### SFTP (Secure File Transfer Protocol)

    A network protocol that provides file access, file transfer, and file management over any reliable data stream designed by the Internet Engineering Task Force (IETF) as an extension of the Secure Shell protocol (SSH) version 2.0 to provide secure file transfer capabilities.

### SMTP (Simple Mail Transfer Protocol)

    An Internet standard for electronic mail (email) transmission.

### SNMP (Simple Network Management Protocol)

    An Internet Standard protocol for collecting and organizing information about managed devices on IP networks and for modifying that information to change device behavior.

### SSL (Secure Sockets Layer)

    An outdated encryption protocol replaced by Transport Layer Security (TLS).

### TCP (Transmission Control Protocol)

    One of the main protocols of the Internet protocol suite, which provides reliable, ordered, and error-checked delivery of a stream of octets (bytes) between applications running on hosts communicating via an IP network.

### TCP/IP (Transmission Control Protocol/Internet Protocol)

    Known as the Internet protocol suite, the conceptual model and set of communications protocols used in the Internet and similar computer networks.

### URL (Uniform Resource Locator)

    A reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it.

### VoIP (Voice over Internet Protocol)

    A method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet.

## Assessments

* Flashcards: Quizlet: IT Fundamentals - Internet
* Quiz: Quizlet: IT Fundamentals - Internet

## See Also

* Internet Fundamentals