“https://www.holbertonschool.com” + “Enter”: Behind the scenes.
You could say that simple is life, only with a click or press button “enter”. However, hold on! It is not too straightforward. Let us see when you put in your search bar some address it is starting a very long journey that is ruled under the web stack scheme. the are different kinds of configurations for web stack, all depend on the purposes of your page, here there is one:
This diagram in simple words has 3 servers (1 Load balancer, 2 Web server, 1 App server, a Database, a Firewall and Client monitory) every server has his own adress (ip), we going to explain deep later!!
First it is important to know the Client-Server Model that is a software design model in which tasks are divided between the providers of resources or services, called servers, and the demanders, called clients. A client makes requests to another program, the server, which gives it a response. This idea can also be applied to programs that run on a single computer, although it is more advantageous in a multi-user operating system distributed over a computer network.
Now let’s clarify some topics:
DNS request
A user opens a web browser, enters www.holbertonschool.com in the address bar, and hits Enter. The request for www.holbertonschool.com is sent to a DNS resolver, which is typically managed by the user’s Internet Service Provider (ISP), such as a cable Internet provider, DSL broadband provider, or corporate network. The ISP’s DNS resolver forwards the request for www.holbertonschool.com to a DNS root name server. The ISP’s DNS resolver forwards the request for www.holbertonschool.com again, this time to one of the TLD nameservers for .com domains. The name server for .com domains responds to the request with the names of the four nameservers that are associated with the holberton.com domain. The ISP’s DNS resolver chooses a nameserver and forwards the request for www.holbertonschool.com to that server. The nameserver searches the hosted zone for holbertonschool.com for the record for www.holbertonschool.com, gets the associated value, such as the web server’s IP address, 4.3.2.1, and returns the IP address to the DNS resolver. The ISP’s DNS resolver finally gets the IP address that the user needs. The solver returns that value to the web browser. The DNS resolver also caches the IP address of holbertonschool.com for a period of time that you specify so that it can respond more quickly the next time someone searches for example.com. For more information, see Time to Live (TTL). The web browser sends a request from www.holbertonschool.com to the IP address it obtained from the DNS resolver. This is where your content is located the web server or other resource in 4.3.2.1 returns the web page for www.holbertonschool.com to the web browser and it displays the page.
TCP/IP
TCP / IP is a set of protocols that allow communication between computers belonging to a network. The acronym TCP / IP stands for Transmission Control Protocol / Internet Protocol. It comes from the names of two important protocols included in the TCP / IP suite, that is, the TCP protocol and the IP protocol.
Firewall
It is a system whose function is to prevent and protect our private network from intrusions or attacks from other networks, blocking access. Allows incoming and outgoing traffic between networks or computers on the same network. If this traffic complies with the previously specified rules, it will be able to access and leave our network, if it does not comply with them, this traffic is blocked. In this way we prevent unauthorized users from accessing our private networks connected to the internet. It can be implemented in the form of hardware, software, or a combination of both.
HTTPS/SSL
SSL is the acronym for Secure Sockets Layer, the standard technology for keeping an Internet connection secure, as well as to protect any confidential information that is sent between two systems and to prevent criminals from reading and modifying any data that is transferred, including information that could be considered personal. The two systems can be a server and a client (for example, a shopping website and a browser) or from server to server (for example, an application with personally identifiable information or payroll data). HTTPS (Hyper Text Transfer Protocol Secure) appears in the URL when a website is protected by an SSL certificate.
Load-balancer
Load balancing is a concept used in computing that refers to the technique used to share the work to be carried out between several processes, computers, disks or other resources. It is closely linked to multiprocessing systems, or that make use of more than one processing unit to perform useful tasks. The load balance is maintained thanks to an algorithm that divides the work in the most equitable way possible, to avoid so-called bottlenecks.
Web server
The main role of a web server is to store and transmit the content requested from a website to the user’s browser. This process, for Internet users, does not last more than a second, however, at the web server level it is a more complicated sequence than it seems. To fulfill its functions, the server must have the ability to be always on to avoid interrupting the service it offers to its clients. If said server fails or shuts down, Internet users will have problems entering the website.
Application server
This is usually a software device that provides application services to client computers. An application server typically handles most (or all) of the application data access and negotiation logic functions. The main benefits of applying application server technology are centralization and less complexity in application development.
Database
A database is a “warehouse” that allows us to store large amounts of information in an organized way so that we can easily find and use it later. Here is a guide that will explain the concept and characteristics of databases. A database can be defined as a set of related information that is grouped or structured. From the computer point of view, the database is a system made up of a set of data stored on disks that allow direct access to them and a set of programs that manipulate that set of data.
