Final Exam

A web hosting service is a type of Internet hosting service that allows individuals and organizations to provide their own website accessible via the World Wide Web. Web hosts are companies that provide space on a server they own for use by their clients as well as providing Internet connectivity, typically in a data center. Web hosts can also provide data center space and connectivity to the Internet for servers they do not own to be located in their data center, called colocation.

The scope of hosting services varies widely. The most basic is web page and small-scale file hosting, where files can be uploaded via File Transfer Protocol (FTP) or a Web interface. The files are usually delivered to the Web "as is" or with little processing. Many Internet service providers (ISPs) offer this service free to their subscribers. People can also obtain Web page hosting from other, alternative service providers. Personal web site hosting is typically free, advertisement-sponsored, or cheap. Business web site hosting often has a higher expense.
Single page hosting is generally sufficient only for personal web pages. A complex site calls for a more comprehensive package that provides database support and application development platforms (e.g. PHP, Java, Ruby on Rails, and ASP.NET). These facilities allow the customers to write or install scripts for applications like forums and content management. For e-commerce, SSL is also required.
The host may also provide an interface or control panel for managing the Web server and installing scripts as well as other services like e-mail. Some hosts specialize in certain software or services (e.g. e-commerce). They are commonly used by larger companies to outsource network infrastructure to a hosting company. To find a web hosting company, searchable directories can be used. One must be extremely careful when searching for a new company because many of the people promoting service providers are actually affiliates and the reviews are biased.


Multiple racks of servers, and how a datacenter commonly looks.
Hosting uptime refers to the percentage of time the host is accessible via the internet. Many providers state that they aim for a 99.9% uptime, but there may be server restarts and planned (or unplanned) maintenance in any hosting environment.
A common claim from the popular hosting providers is '99% or 99.9% server uptime' but this often refers only to a server being powered on and doesn't account for network downtime. Real downtime can potentially be larger than the percentage guaranteed by the provider. Many providers tie uptime and accessibility into their own service level agreement (SLA). SLAs sometimes include refunds or reduced costs if performance goals are not met.



A typical server "cage," commonly seen in colocation centres.
Internet hosting services can run Web servers; see Internet hosting services.
Hosting services limited to the Web:
Free web hosting service: is free, (sometimes) advertisement-supported web hosting, and is often limited when compared to paid hosting.
Shared web hosting service: one's Web site is placed on the same server as many other sites, ranging from a few to hundreds or thousands. Typically, all domains may share a common pool of server resources, such as RAM and the CPU. A shared website may be hosted with a reseller.
Reseller web hosting: allows clients to become web hosts themselves. Resellers could function, for individual domains, under any combination of these listed types of hosting, depending on who they are affiliated with as a provider. Resellers' accounts may vary tremendously in size: they may have their own virtual dedicated server to a colocated server.
Virtual Dedicated Server: dividing a server into virtual servers, where each user feels like they're on their own dedicated server, but they're actually sharing a server with many other users. The users may have root access to their own virtual space. This is also known as a virtual private server or VPS.
Dedicated hosting service: the user gets his or her own Web server and gains full control over it (root access for Linux/administrator access for Windows); however, the user typically does not own the server. Another type of Dedicated hosting is Self-Managed or Unmanaged. This is usually the least expensive for Dedicated plans. The user has full administrative access to the box, which means the client is responsible for the security and maintenance of his own dedicated box.
Managed hosting service: the user gets his or her own Web server but is not allowed full control over it (root access for Linux/administrator access for Windows); however, they are allowed to manage their data via FTP or other remote management tools. The user is disallowed full control so that the provider can guarantee quality of service by not allowing the user to modify the server or potentially create configuration problems. The user typically does not own the server. The server is leased to the client.
Colocation web hosting service: similar to the dedicated web hosting service, but the user owns the colo server; the hosting company provides physical space that the server takes up and takes care of the server. This is the most powerful and expensive type of the web hosting service. In most cases, the colocation provider may provide little to no support directly for their client's machine, providing only the electrical, Internet access, and storage facilities for the server. In most cases for colo, the client would have his own administrator visit the data center on site to do any hardware upgrades or changes.
Clustered hosting: having multiple servers hosting the same content for better resource utilization. Clustered Servers are a perfect solution for high-availability dedicated hosting, or creating a scalable web hosting solution.
Grid hosting : this form of distributed hosting is when a server cluster acts like a grid and is composed of multiple nodes.
Home server: usually a single machine placed in a private residence can be used to host one or more web sites from a usually consumer-grade broadband connection. These can be purpose-built machines or more commonly old PC's.
Some ISPs actively attempt to block these servers by disallowing incoming requests to TCP port 80 of the user's connection and by refusing to provide static IP addresses. A common way to attain a static IP is by creating an account with a dynamic DNS service. A dynamic DNS service will automatically change the IP address that a URL points to when it changes.
Some specific types of hosting provided by web host service providers:
File hosting service: hosts not web pages but files
Image hosting service
Video hosting service
Blog hosting service
One-click hosting
Shopping cart software

Web hosting is often provided as part of a general Internet access plan; there are many free and paid providers offering these services.
A customer needs to evaluate the requirements of the application to choose what kind of hosting to use. Such considerations include database server software, scripting software, and operating system. Most hosting providers provide Linux-based web hosting which offers a wide range of different software. A typical configuration for a Linux server is the LAMP platform: Linux, Apache, MySQL, and PHP/Perl/Python. The webhosting client may want to have other services, such as email for their business domain, databases or multi-media services for streaming media. A customer may also choose Windows for its hosting platform. The customer still can choose from PHP, Perl, and Python but may also use ASP .Net or Classic ASP.
Web hosting packages often include a Web Content Management System, so the end-user doesn't have to worry about the more technical aspects. These Web Content Management systems are great for the average user, but for those who want more control over their website design, this feature can sometimes be a nuisance rather than a feature.
One may also search the Internet to find active webhosting message boards that may provide feedback on what type of webhosting company may suit his/her needs.