What is a Web Server?

A web server is a computer system combined with software used for the storing and serving of website files. Every time a user goes to a website, their client – a browser – requests the web page’s contents from the web server. In turn, the web site server delivers this to the user’s client.

Definition of a web server

Every time you visit a website, you are actually engaging with a web server to retrieve the web page you wish to view. The server responds to your request by sending the web page to your computer or device before you can view it in your web browser (known as a web client).

Most people imagine web servers as hardware located in a data centre, working through requests. In reality, yes, the physical hardware of the web server stores and sends files to clients – but needs software to process any request and instruct the hardware what data should be sent back to the client.

Why a web server is vital

A web server is required if you wish to create and publish a website. This can be created on-premise via an IT team or more typically, many companies turn to a hosting provider. These allow you to purchase a web hosting solution – rent space on the provider’s web server – as well as register a domain name for the website. A web hosting provider can also offer additional services including site building tools, email hosting, and more.

Finally if you’re wondering whether an internet server is the same as a web server, not quite. Internet servers provide services over the net while web servers are used to manage incoming requests for web pages.

Websites (HTTP)

Web servers use HTTP (Hypertext Transfer Protocol) software to respond to your request for web page data, which is typically made up of HTML, CSS and JavaScript files as well as images. This is how the process breaks down:

You enter the web address – its URL – that you wish to visit into your browser
Your browser makes a request for the web page – or actually the files that make up the page – using HTTP.
Your request is received by the web server and the HTTP software accepts your request.
The HTTP software locates the files before sending them back to your browser.
The browser process the files, creating the web page for you.
You can now view and interact with the web page.

Here are some of the errors that can be displayed if there is an issue with the request:

If the web page’s file cannot be located, you get a Error 404 message.
If the web page’s file has permission issues, you will get a Error 403 message.
If the web server is relying on another server to source the requested file but does not receive a response within a set period of time, you will get the 504 error.

Email (SMTP)

Web servers also manage your email requests via the Simple Mail Transfer Protocol (SMTP):

You write your email and send it via your email client.
Your client contacts your web site server and once an connection is established, sends your email file to the server.
In turn, the web site server then processes and passes on the email file to the recipient’s web server.
This server delivers the email to the recipient’s email client – its inbox – where it sits waiting to be read.

In other words, the web server acts a postal service, always available to send your messages – or deliver them if it receives an email addressed to you.

Storage (FTP)

Web servers offer a secure data storage option using File Transfer Protocol (FTP). FTP allows you to safely upload and download your files for storage on the web server. Imagine FTP as a secure channel that links your computer with the server that can – with the right permissions – be accessed from wherever you are.

What are other key web server features?

To support its core functionality of managing web page requests, web servers offer a range of other useful features to aid enterprise. These include file logging where, every time a web server performs an action, it’s logged so you can see exactly what activities or events have been conducted. Authentication processes are also provided, requiring users to enter a username and password before being able to access any resources held on the web server.

To effectively manage incoming traffic, high quality web servers use load balancing to provide fast response times, ensuring that any one server doesn’t become overloaded. Instead, incoming traffic is spread across several servers (see below for more details about server farms). This feature can be used in parallel with bandwidth limiting, which controls the web server’s response-to-user-request speeds. Such limiting ensures web server response times are standardised to deliver a consistent service that is optimised for smooth user experiences.

What is the difference between static vs dynamic web servers?

What are web servers: Static

A static web server delivers content that is ‘static’, i.e., fixed content such as text and images that do not offer any interactivity (save for hyperlinks) – just content that you can browse through. Examples? Pages such as this one or within an enterprise setting, simple web pages such as About Us or Blogs. In other words, a static web server acts as a library – in technical terms, a content delivery network – with books (web pages) that can be browsed through, but feature no interactivity or dynamic elements.

What are web servers: Dynamic

A dynamic web server is all about enabling change within the web page. The dynamic web server pulls together and presents a web site’s content live either from a database or an application server. Such functionality is essential for sites that are interactive such as e-commerce or social media; in effect, the web server receives a request from a specific user before constructing a page customised to them.

Alternatively, the page may have content that you can change, ergo it needs to be updated live by the dynamic web site server. For instance, you may wish to fill in a form or send goods to your shopping basket. All these are moving parts that the dynamic web server can manage, process and deliver in real-time.

What are different types of web servers?

Dedicated web servers

This is a single web site server with installed server software that is either owned or rented by the enterprise. A dedicated web server is the ideal solution for companies that want exclusive access – i.e., they are not sharing the server’s resources with anyone else – plus demand total control over every aspect of the web server from its configuration and software setup through to what security measures are deployed. Finally, a dedicated web site server offers the best possible performance because it’s only ever used by the company. The downsides?:

It’s more costly than other solutions so expect increased server fees.
You’ll need to update and maintain the solution on a rolling basis to ensure smooth operations and optimised security.
Dedicated web severs represent significant logistical challenges without the right in-house talent.

Shared web servers

These are single servers provided by web hosts that are used to serve multiple websites from different clients. The upside is simple – it’s a far more cost-effective solution than a dedicated web server. You also benefit from any updating and maintenance being carried out by the provider, negating the need for a dedicated in-house team. However, there can be downsides.

For instance:

You are sharing server resources with other companies – and their website traffic – which can effect performance if there are traffic spikes.
Customisation options are typically curtailed as the solution is standardised to deliver for multiple clients at once, instead of offering the bespoke benefits of a dedicated web server.

To give you the best possible experience using a web hosting plan, OVHcloud monitors resource consumption and traffic. If a client overconsumes, its service is isolated on another server, so that it does not affect other users.

Virtual web server

Perhaps offering the best compromise between a dedicated web site server and a shared web site server, virtual web servers (VPS) sees a single physical web server being partitioned into a series of virtual servers. This means each virtual server acts as a single dedicated hardware server, enabling an enterprise to dictate what software and security measures are installed. Plus VPSs offer similar cost reduction benefits as a shared web server.

However, there are potential drawbacks:

To effectively manage a VPS, you will require some specialist knowledge of server technology.
The issue of traffic spikes experienced by other clients using the same physical sever will still impact on overall performance levels.
Finally, virtualisation perhaps inevitably introduces an additional set of security concerns that require managing.

What is a server farm?

This is a series of connected servers that helps spread request processing loads. Instead a single server struggling with high volumes of incoming traffic, requests are spread out across multiple servers instead, using load balancing to manage any traffic volumes effectively.

A large enterprise can have its own dedicated server farm to manage the flow of data from different areas of its operations. However, within a web site server context, web server farms are typically used by web hosting providers to successfully manage multiple client requests while delivering and maintaining acceptable performance levels.

What are popular web server software solutions?

To ensure web servers can actually understand and manage requests, a web server application must be installed on the web server hardware. The most popular apps include:

Apache HTTP web server software

This is one of the world’s most popular web site server software solutions. Open source and available at no cost, Apache can be installed on all the leading operating systems including Windows, Linux and macOS. It enables enterprise – or host providers – to host and manage multiple services, apps and dynamic/static websites on a web server/s.

Internet Information Service

Developed by Microsoft, this web server application is often used on Windows-based servers. Like Apache, it can host multiple services as well as help create dynamic and static web pages thanks to its server-side scripting technology called Active Server Pages.

NGINX

A free open-source application, NGINX is optimised for serving high traffic volumes thanks to its advanced load-balancing capabilities. Available for operation systems including Windows, Linux and MacOs, there are currently over 350 million websites relying on the application to deliver content to users.

How is web server performance measured?

There are several parameters used to define overall web server performance, offering unique insights and analytics of how well client requests are being serviced. Key parameters include:

Concurrency

Important to creating the context for all the other parameters listed here, concurrency highlights the number of requests being processed by the web site server at any one time based on server configuration, operating system, available resources, and more.

Requests per second (RPS)

RPS measures the number of requests being processed in a single second. This is important for formulating how much capacity the server has to manage multiple client requests at the same time.

Throughput

Measuring the amount of data being transferred between the server and the client within a defined time period, the aim should be to have a throughput as high as possible.

Latency

Conversely, latency is the time delay between a request being sent by the client and a response being delivered back to them by the web site server. This means the desired latency figure should be as low as possible.

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