In computing, it is known as a server (from the English server) to a computer that is part of a computer network and provides certain services to the rest of the computers, called stations or clients. Said computers must have a specific application capable of meeting the requests of the different clients and providing them with a timely response. In reality, several simultaneous servers ( software ) can function within the same physical computer ( hardware ), as long as they have the necessary logistical resources.
The servers operate based on a client-server communication model (or “architecture”), dividing the tasks among the providers of available resources, thus offering their clients the opportunity to share data, specific information and access to certain resources of software and hardware, such as a specific application or peripheral. This is how, for example, web pages and email services work.
Commonly, servers can be classified according to their availability into dedicated and shared. Dedicated servers have all their hardware and processing resources to serve customer requests, while shared servers are those that, in addition to receiving requests from clients through the network, serve processes locally, outside the network.
Characteristics of a server
Since servers are computers in charge of meeting the demands of network clients, one of their main characteristics is that they must have their resources constantly available so that the network is operational all the time. In other words, they must always be on, always available. This is why sometimes a web page or its resources cannot be loaded: if a server crashes or crashes, a certain segment of the network that it is in charge of will no longer be available to its clientele.
On the other hand, servers are usually high-end computers, equipped with sufficient processing capacity to serve numerous client requests with a minimum range of delay. This also implies having a constant supply of electricity and other physical resources to guarantee its operability. In fact, in many cases, servers are stored in very well-conditioned compartments, even climatically: in a sufficiently cool and dust-free environment, system overheating is avoided.
What is a server for?
As we have said, the servers are in charge of attending to the clients’ requests of a certain network and managing the resources available to it so that each client can access the information or peripherals they need. In that sense, servers can have very different functions, such as:
- File servers. They store the files or files of information and feed them to a network.
- Active Directory / Domain Servers. They manage information related to the network, its users, computers and internal groups.
- Print server. It manages a set of printers available to a network, granting access to them and managing the print queue.
- Mail server. It manages the flow of e-mail between, from and to the clients of a network, sending and receiving messages and storing their history.
- Proxy server. Its role is backup, storing for a time. In memory, a copy of the web pages available for the network, speeding up access to them or allowing data recovery if the original one goes down.
- Web server. It stores the content necessary for one or more web pages and manages the orderly access to it so that the clients’ browsers can “render” a website.
- DNS server. Stores the information required to associate a domain name with a series of IP addresses of the computers linked to it (its web servers).
- DHCP server. In charge of assigning dynamic (changing) IP addresses to clients that connect to a network.
- FTP server. It stores specific user information and allows private access to it between computers.
- Game server. Those specifically dedicated to storing information so that customers can access a recreational program simultaneously (massive video games, generally).
Web servers are programs (software) for daily use on the Internet, which mediate between the server in which the data requested by the client is hosted and their computer, allowing connections through various data protocols, such as the well-known HTTP (HyperText Transfer Protocol, or Hypertext Transfer Protocol ). In other words, they are programs that mediate between the browser of an Internet user and the place where the information he is looking for or needs resides.
This term is also used to refer to the computer itself (hardware) in which the files that make up a website are stored and the software necessary to comply with the web data connection.
Types of web servers
Web servers can be of two kinds, depending on their content:
- Static servers. This is the name given to the computers where the information that the user seeks is stored and the HTTP server that responds to the data request protocols. The requested files are sent as they are stored, whether there are errors or not, and that is where their name comes from.
- Dynamic servers. In this case, they are servers identical to the static ones, but which contain additional software (such as applications and databases ), which allows them to update the information requested by the client before sending it through the web.
Examples of web servers
Some of the most used web servers are the following:
- Nginx. A web server and proxy developed by the eponymous company in 2004.
- Internet Information Services or IIS. A web server and set of services designed for Microsoft Windows were originally included in its NT version.
- Cherokee. A multiplatform web server is written in the C language, available under the GNU General Public License ( free software ).
- Tomcat. A 1999 Apache distribution, also known as Jakarta Tomcat, operates on the principle of servlets (Java).