Client-server

1) Client-server architecture

Client Server Architecture is a computing model in which the server hosts, delivers and manages most of the resources and services to be consumed by the client. This type of architecture has one or more client computers connected to a central server over a network or internet connection.

2) What is HTTP and HTTPS

HTTP stands for Hyper Text Transfer Protocol.

The Hypertext Transfer Protocol is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems.

3) HTTP methods

The primary or most commonly-used HTTP methods are POST, GET, PUT, PATCH, and DELETE.

These methods correspond to create, read, update, and delete (or CRUD) operations, respectively.

There are a number of other methods, too, but they are utilized less frequently.

4) HTTP status codes of the server

An HTTP status code is a server response to a browser's request.

When you visit a website, your browser sends a request to the site's server, and the server then responds to the browser's request with a three-digit code: the HTTP status code.

HTTP response status codes:

Informational responses ( 100 – 199 )

Successful responses ( 200 – 299 )

Redirection messages ( 300 – 399 )

Client error responses ( 400 – 499 )

Server error responses ( 500 – 599 )

5) What is the browser core

A browser engine (also known as a layout engine or rendering engine) is a core software component of every major web browser.

The primary job of a browser engine is to transform HTML documents and other resources of a web page into an interactive visual representation on a user's device.

6) Which browsers use which kernels

Blink – Used in Google Chrome, and Opera browsers.

WebKit – Used in Safari browsers.

Gecko – Used in Mozilla Firefox browsers.

Trident – Used in Internet Explorer browsers.

EdgeHTML – Used in Edge browsers.

Presto – Legacy rendering engine for Opera.

7) What is API

An application programming interface is a connection between computers or between computer programs.

It is a type of software interface, offering a service to other pieces of software.

A document or standard that describes how to build or use such a connection or interface is called an API specification.

8) What are endpoints

A communication endpoint is a type of communication network node. It is an interface exposed by a communicating party or by a communication channel.

An example of the latter type of a communication endpoint is a publish-subscribe topic or a group in group communication systems.

9) URL (URI, URL, URN)

URI (uniform resource identifier) identifies a resource (text document, image file, etc).

URL (uniform resource locator) is a subset of the URIs that include a network location.

URN (uniform resource name) is a subset of URIs that include a name within a given space, but no location.

10) Idempotent HTTP Methods

An HTTP method is idempotent if an identical request can be made once or several times in a row with the same effect while leaving the server in the same state.

In other words, an idempotent method should not have any side-effects (except for keeping statistics).

11) Secure HTTP Methods

Several common HTTP methods are safe: GET , HEAD , or OPTIONS . All safe methods are also idempotent, but not all idempotent methods are safe.

For example, PUT and DELETE are both idempotent but unsafe.

Even if safe methods have a read-only semantic, servers can alter their state: e.g. they can log or keep statistics.

12) Identification, Authentication, Authorization

Identification is the claim of a subject of its identity.

Authentication is the proof of identity that is achieved through providing credentials to the access control mechanism.

Authorization is the mechanism that determines the access level(s) of the subjects to the objects

13) What is IP

An Internet Protocol address is a numerical label that is connected to a computer network that uses the Internet Protocol for communication.

An IP address serves two main functions: network interface identification and location addressing.

14) What is a port, how many ports does a Linux server have

The port numbers are divided into three ranges: Well Known Ports: those from 0 through 1023.

Registered Ports: those from 1024 through 49151.

Dynamic and/or Private Ports: those from 49152 through 65535.

Linux server has 65536 ports.

15) OSI layers

7 levels that can be divided into 2 groups

Media Layers

1) Physical layer

2) Data link layer

3) Network layer

Host layers

4) Transport layer

5) Session layer

6) Presentation layer

7) Application layer

16) http request headers

An HTTP request header is a component of a network packet sent by a browser or client to the server to request for a specific page or data on the Web server.

It is used in Web communications or Internet browsing to transport user requests to the corresponding website's Web server.