Web hosting service
A web hosting service is a type of Internet
hosting service that allows individuals and organizations to make their website
accessible via the World Wide Web. Web hosts are companies that provide space
on a server owned or leased for use by 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 other servers located in
their data center, called colocation, also known as Housing in Latin America or
France.
History
Until 1991, the Internet was restricted to
use only ...for research and education in the sciences and engineering... and
was used for email, telnet, FTP and USENET traffic - but only a tiny number of
web pages. The World Wide Web protocols had only just been written and not
until the end of 1993 would there be a graphical web browser for Mac or Windows
computers. Even after there was some opening up of internet access, the situation
was confused until 1995.
To host a website on the internet, an
individual or company would need their own computer or server. As not all
companies had the budget or expertise to do this, web hosting services began to
offer to host users' websites on their own servers, without the client needing
to own the necessary infrastructure required to operate the website. The owners
of the websites, also called webmasters, would be able to create a website that
would be hosted on the web hosting service's server and published to the web by
the web hosting service.
As the number of users on the World Wide Web
grew, the pressure for companies, both large and small, to have an online
presence grew. By 1995, companies such as GeoCities, Angelfire and Tripod were
offering free hosting.
Classification
- Smaller hosting services
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 minimal processing. Many Internet service providers (ISPs) offer this
service free to subscribers. Individuals and organizations may also obtain Web
page hosting from alternative service providers.
Free web hosting service is offered by
different companies with limited services, sometimes supported by
advertisements, and often limited when compared to paid hosting.
Single page hosting is generally sufficient
for personal web pages. Personal web site hosting is typically free,
advertisement-sponsored, or inexpensive. Business web site hosting often has a
higher expense depending upon the size and type of the site.
- Larger hosting services
Many large companies that are not Internet
service providers need to be permanently connected to the web to send email,
files, etc. to other sites. The company may use the computer as a website host
to provide details of their goods and services and facilities for online
orders.
A complex site calls for a more comprehensive
package that provides database support and application development platforms
(e.g. ASP.NET, ColdFusion, Java EE, Perl/Plack, PHP or Ruby on Rails). These
facilities allow customers to write or install scripts for applications like
forums and content management. Also, Secure Sockets Layer (SSL) is typically
used for websites that wish to keep the data transmitted more secure.
Types of hosting
A typical server "rack" commonly
seen in colocation centres. Internet hosting services can run Web
servers. The scope of web hosting services varies greatly.
- Shared web hosting service
One's website is placed on the same server as
many other sites, ranging from a few sites to hundreds of websites. Typically,
all domains may share a common pool of server resources, such as RAM and the
CPU. The features available with this type of service can be quite basic and
not flexible in terms of software and updates. Resellers often sell shared web
hosting and web companies often have reseller accounts to provide hosting for
clients.
- 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 reseller. Resellers' accounts may vary tremendously in
size: they may have their own virtual dedicated server to a colocated server.
Many resellers provide a nearly identical service to their provider's shared
hosting plan and provide the technical support themselves.
- Virtual Dedicated Server
Also known as a Virtual Private Server (VPS),
divides server resources into virtual servers, where resources can be allocated
in a way that does not directly reflect the underlying hardware. VPS will often
be allocated resources based on a one server to many VPSs relationship, however
virtualisation may be done for a number of reasons, including the ability to
move a VPS container between servers. The users may have root access to their
own virtual space. Customers are sometimes responsible for patching and
maintaining the server (unmanaged server) or the VPS provider may provide
server admin tasks for the customer (managed server).
- Dedicated hosting service
The user gets his or her own Web server and
gains full control over it (user has root access for Linux/administrator access
for Windows); however, the user typically does not own the server. One 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 server,
which means the client is responsible for the security and maintenance of his
own dedicated server.
- Managed hosting service
The user gets his or her own Web server but
is not allowed full control over it (user is denied 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 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. Formerly, many colocation providers would accept any system
configuration for hosting, even ones housed in desktop-style minitower cases,
but most hosts now require rack mount enclosures and standard system
configurations.
- Cloud hosting
This is a new type of hosting platform that
allows customers powerful, scalable and reliable hosting based on clustered
load-balanced servers and utility billing. A cloud hosted website may be more
reliable than alternatives since other computers in the cloud can compensate
when a single piece of hardware goes down. Also, local power disruptions or
even natural disasters are less problematic for cloud hosted sites, as cloud
hosting is decentralized. Cloud hosting also allows providers to charge users
only for resources consumed by the user, rather than a flat fee for the amount
the user expects they will use, or a fixed cost upfront hardware investment.
Alternatively, the lack of centralization may give users less control on where
their data is located which could be a problem for users with data security or
privacy concerns.
- 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. A cluster may separate web serving from database hosting
capability. (Usually web hosts use clustered hosting for their shared hosting
plans, as there are multiple benefits to the mass managing of clients).
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 PCs. Some ISPs actively attempt to block home 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 reliable DNS
host name 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 the
IP address changes.
Some specific types of hosting provided by
web host service providers:
- File hosting service: hosts files, not web pages
- Image hosting service
- Video hosting service
- Blog hosting service
- Paste bin
- Shopping cart software
- E-mail hosting service
- Host management
Multiple racks of servers
The host may also provide an interface or
control panel for managing the Web server and installing scripts, as well as
other modules and service applications like e-mail. A web server that does not
use a control panel for managing the hosting account, is often referred to as a
"headless" server. Some hosts specialize in certain software or
services (e.g. e-commerce, blogs, etc.).
Reliability and uptime
The availability of a website is measured by
the percentage of a year in which the website is publicly accessible and
reachable via the Internet. This is different from measuring the uptime of a
system. Uptime refers to the system itself being online. Uptime does not take
into account being able to reach it as in the event of a network
outage.[citation needed] A hosting provider's Service Level Agreement (SLA) may
include a certain amount of scheduled downtime per year in order to perform
maintenance on the systems. This scheduled downtime is often excluded from the
SLA timeframe, and needs to be subtracted from the Total Time when availability
is calculated. Depending on the wording of an SLA, if the availability of a
system drops below that in the signed SLA, a hosting provider often will
provide a partial refund for time lost. How downtime is determined changes from
provider to provider, therefore reading the SLA is imperative.Not all providers
release uptime statistics.Most hosting providers will guarantee at least 99.9%
uptime which will allow for 43m of downtime per month, or 8h 45m of downtime
per year.
Obtaining hosting
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Unsourced material may be challenged and removed. (June 2015) (Learn how and
when to remove this template message) .Web hosting is often provided as part of a
general Internet access plan from Internet service providers. There are also
many free and paid providers offering web hosting.
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 web hosting
client may want to have other services, such as email for their business
domain, databases or multimedia services. A customer may also choose Windows as
the hosting platform. The customer still can choose from Perl, PHP, Python, and
Ruby, but the customer may also use ASP.NET or ASP Classic. Web hosting
packages often include a web content management system, so the end-user does
not have to worry about the more technical aspects.
Security
Because web hosting services host websites
belonging to their customers, online security is an important concern. When a
customer agrees to use a web hosting service, they are relinquishing control of
the security of their site to the company that is hosting the site. The level
of security that a web hosting service offers is extremely important to a
prospective customer and can be a major consideration when considering which
provider a customer may choose.
Web hosting servers can be attacked by
malicious users in different ways, including uploading malware or malicious
code onto a hosted website. These attacks may be done for different reasons,
including stealing credit card data, launching a Distributed Denial of Service
Attack (DDoS) or spamming.
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