The Internet and Core Technologies Flashcards
What does TCP/IP stand for?
The transmission control protocol and internet protocol
What is the difference between the internet and the world wide web?
The world wide web, or web for short, are the pages you see when you’re at a device and you’re online.
But the internet is the network of connected computers that the web works on. Think of the internet as the roads that connect towns and cities together. The world wide web contains the things you see on the roads like houses and shops.
What is the client-server model?
Client/server is a model of interaction in which a program sends a request to another program and awaits a response.
The client refers to the user’s device or program that is making a request for data. A client can be a browser or application running on a user’s laptop, smartphone, or tablet.
The server is the device or program in that network that waits for incoming requests and sends back data.
What is the job of the server?
The server is dedicated to holding the websites files. Servers contain logic for processing a request and identifying the files and data that the client has specified. It will respond to the browser’s request with the necessary files.
What is a server?
A server is a specialized computer connected to a network which provides, or “serves up”, resources or services.
How do browsers and servers communicate?
The browser and server communicate with each other using the internet protocol HTTP (hypertext transfer protocol), which allows for data transfer.
What’s the role of the browser?
The browser initiates a request to the server and renders website files.
What is HTTP?
HTTP stands for hypertext transfer protocol and is a standardized set of rules for how browsers and servers transfer data to one another.
What are status codes?
When a server responds to a client, the server specifies a status code as a part of the response. Status codes indicate whether or not the HTTP request was successfully completed and if there was an error, they contain some information about the type of error that happened.
What does the 404 code mean?
The requested resource was not found
How do web browsers work?
Every time we load a webpage, our device sends a request for each file that makes up that page.
1.When a user types in a URL and presses enter, the server processes the request and sends the HTML file back to the client. The HTML file holds content and links to display the site properly.
2.The browser will begin to search for elements in the HTML file and it will start to make additional HTTP requests for any other external resources used by the HTML file. This often includes:
a.) One or more CSS stylesheets.The browser analyzes the CSS and starts applying the visual styles to the content of the site.
b.) Website assets, like images and videos, from the server to the browser.
c.) One or more JavaScript files.
What are static web pages?
Static web pages are web pages that do not respond to user behavior and the content is the same for all users.
How is web 2.0 different than web 1.0?
Web 2.0:
1. Provides a dynamic user experience by offering content that responds to user input without forcing the page to reload.
2. Emphasizes user-generated content and social sharing.
What’s the function of the Console tab in Chrome developer tools?
The Console tab that outputs JavaScript logs and errors from a web application
What’s the function of the Sources tab in Chrome developer tools?
The Sources tab shows all content resolved for the current page. The Sources tab includes HTML, CSS, JavaScript, images and videos.
What’s the function of the Network tab in Chrome developer tools?
The Network tab allows you to inspect the timeline and details of HTTP requests and responses for a webpage.
What’s the function of the Memory tab in Chrome developer tools?
The Memory tab displays the parts of your code that are consuming the most resources. This feature helps to identify if and where your code needs improvement.
What’s the function of the Performance tab in Chrome developer tools?
The Performance tab shows what the web browser is doing over time. It can help you identify functions that are taking the most time if your web application is running slow.
What is an IP address?
It’s a unique string of characters that identifies each computer using the Internet Protocol to communicate over a network.
What is an Internet Protocol and which ones are typically in use?
IP is a set of rules governing the format of data sent over the internet or other network. Version four and version six are currently the two most widely used standards of internet protocol.
What is the difference between IP4 and IP6 address?
In protocol version four an IP address contains four octet. It’s separated by periods or dots. For example 192.0.2.235. In protocol version six. An IP address contains eight groups of hexadecimal digits separated by a colon. For example 4527:0a00:1567:0200:ff00:0042:8329.
What are IP packets?
IP packets are structures that carry data during transmission on an IP network. When you send data across a network, you send the data as a series of messages called IP packets. They are also known as data grams.
What are the component parts of an IP packet?
At a high level IP packets contain a header and a payload or the data. They include the destination IP address and source IP address. These addresses are in the header along with some additional information to help deliver the packet. And the payload contains the data of the packet and some of the other protocols, mainly the TCP and the UDP, which contain payloads that contain further protocols inside of them.
What are the three typical issues with IP packet delivery?
These issues are:
1. they can arrive out of order,
2. they can become damaged or corrupted in transit or
3. they can be dropped or lost during transit.
What are the two most common protocols in the IP packet payload?
Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP). Both of these protocols contain payloads that contain further protocols inside of them.
What is the TCP?
The Transmission Control Protocol can solve all three of the issues with IP packet delivery (when messages arrive out of order, they become damaged or corrupted in transit or be dropped or lost during transit) but at the cost of a small delay when sending the data.
What is the UDP?
The User Datagram Protocol (UDP) solves the corrupt packet issue but packets can still arrive out of order or not arrive at all. This protocol is used for sending data that can tolerate some data loss such as voice calls or live video streaming.
What are the primary or the most commonly used HTTP methods?
The primary or the most commonly used HTTP methods are GET, POST, PUT and DELETE.
What is GET (HTTP method)?
The GET method is used to retrieve information from the given server.
What is POST (HTTP method)?
The POST request is used to send data to the server.
What is PUT (HTTP method)?
The PUT method updates whatever currently exist on the website with something else
What is DELETE (HTTP method)?
The DELETE method removes the resource.
What is a HTTP request?
Submitting an HTTP request involves sending a message to the receiving server in a specific format.
What are the parts of a HTTP request?
An HTTP request is made out of three components: request line, headers and message body, the last being optional.
Which version of the HTTP protocol is most commonly used?
There are multiple versions of the HTTP protocol and Version 1.1 and 2.0 are the most used.
What is HTTP?
HTTP (Hypertext Transfer Protocol) is the communication protocol you use whenever you browse the web. It’s used for transferring web resources such as HTML documents, images, styles, and other files.
What is the method (in HTTP request)?
The HTTP method describes the type of action that the client was to perform. For certain requests methods, the requests will also contain a body of content that the client is sending.
What is the path (in HTTP request)?
The path is the representation of where the resource is stored on the webserver. For example, if you requested an image at https://example.com/index.html, the path would be /index.html.
What are headers (in HTTP request)?
Headers contain additional information about the request, and the client that is making the request.
What is a HTTP response?
An HTTP response is made by a server to a client. The aim of the response is to provide the client with the resource it requested, or inform the client that the action it requested has been carried out; or else to inform the client that an error occurred in processing its request.
What are the parts of a HTTP response?
HTTP responses follow a format similar to the request format. Following the header, the response will optionally contain a message body consisting of the response contents such as the HTML document, the image file, and so forth.
What are HTTP status codes?
An HTTP status code is a message a website’s server sends to the browser to indicate whether or not that request can be fulfilled.
What are the five groups of status codes and what do they mean?
The status codes are grouped by the first digit of the error number.
1.Informational: 100-199.
2. Successful responses: 200-299.
3. Redirection messages: 300-399.
4. Client error responses: 400-499
5. Server error responses: 500- 599.
Describe the Informational responses and give the most commonly used one.
Information responses are provisional responses sent by the server. These responses are interim before the actual response. The most common response is 100 Continue, which indicates that the web client should continue to request or ignore the response if the request is already finished.
Describe the Successful responses and give the most commonly used one.
Successful responses indicate that the request was successfully processed by the web server, with the most common success response being 200 Ok, which has a meaning depending on the method.
Explain meanings of the 200 Ok.
The meaning of 200 Ok depends on the HTTP method.
If the method is GET, it means that the resource is found and is included in the body of the HTTP response.
If it’s POST, it means that the resource was successfully transmitted to the webserver.
If it’s PUT, the resource was successfully transmitted to the webserver.
Finally, if the method is DELETE, it means the resource was deleted.
Describe the Redirection responses and give the most commonly used ones.
Redirection responses indicate to the web client that the requested resource has been moved to a different path. The most common response codes used are 301 Moved Permanently and 302 Found.
What is the difference between redirection messages 301 and 302?
The difference between the redirection messages 301 (Moved Permanently) and 302 (Found) is that 302 indicates a temporary redirection. The resource has been temporarily moved. When web browsers receive these responses, they will automatically submit the request for the resource at the new path.
Describe the Client error responses.
Client error responses indicate that the requests contained bad syntax or content and cannot be processed by the webserver.
What are the most common Client error responses?
The most common codes used are:
1. 400: used where the web browser or client submitted bad data to the webserver.
2. 401: used to indicate that the user must log into an account before the request can be processed.
3. 403: used to indicate the request was valid, but that the webserver is refusing to process it. This is often used to indicate that a user does not have sufficient permissions to execute an action in a web application.
4. 404: used to indicate that the request resource was not found on the webserver.
Describe the server error responses.
Server error responses indicate that a failure occurred on the webserver while trying to process the request. The most common code used is 500 Internal Server Error, which is a generic error status indicating that the server fail to process the request.
What is the HTTPS and how does it work?
HTTPS is the secure version of HTTP. It is used for secure communication between two computers so that nobody else can see the information being sent and received. Like an HTTP, the requests and responses still behave in the same way and have the same content. The big difference is before the content is sent, it is encrypted (turned into a secret code). Only the other computer can turn the secret code back into its original content. If someone else was to look at the code, it wouldn’t be understandable.
What is 101 code?
Status code 101 Switching Protocols means that the client has requested the server to switch protocols and the server has agreed to do so.
What is 201 code?
Status code 201 Created means that the server successfully processed the request and a resource was created.
What is 202 code?
Status code 202 Accepted means that the server accepted the request for processing but the processing has not yet been completed.
What is 204 code?
Status code 204 No Content means that the server successfully processed the request but is not returning any content.
What is 405 code?
Status code 405 Method Not Allowed means that the web server does not support the HTTP method used.
What is 502 code?
Status code 502 Bad Gateway means that the web server received an invalid response from the Application Server.
What is 503 code?
Status code 503 Service Unavailable means that the web server cannot process the request.
What is a request line (HTTP)? Give an example.
Every HTTP request begins with the request line. This consists of the HTTP method, the requested resource and the HTTP protocol version.
GET /home.html HTTP/1.1
In this example, GET is the HTTP method, /home.html is the resource requested and HTTP 1.1 is the protocol used.
What is a request header (HTTP)? Give an example.
The header of the request is where the headers of the request are located. After the request line, the HTTP headers are followed by a line break.
There are various possibilities when including an HTTP header in the HTTP request. A header is a case-insensitive name followed by a: and then followed by a value.
Host: example.com
In this case, the name of the header is Host, and its value is example.com.
What are HTTP Request Headers?
Headers are metadata that are sent in the request to provide information about that request.
Describe the basic Git workflow
The Git workflow consists of editing files in the working directory, adding files to the staging area, and saving changes to a Git repository.
