Shared hosting services typically offer basic web statistics support, email and web mail services, auto script installations, updated PHP and MySQL, basic after-sale technical support that is included with a monthly subscription. It also typically uses a web-based control panel system, such as cPanel, DirectAdmin, Plesk, InterWorx, H-Sphere or one of many other control panel products. Most of the large hosting companies use their own custom developed control panel. Control panels and web interfaces can cause controversy however, since web hosting companies sometimes sell the right to use their control panel system to others. Attempting to recreate the functionality of a specific control panel is common, which leads to many lawsuits over patent infringement.
In shared hosting, the provider is generally responsible for managing servers, installing server software, security updates, technical support, and other aspects of the service. Most servers are based on the Linux operating system and LAMP (software bundle), which is driven by the reliability and security of open source software such as Linux and Apache (the 'L' and 'A' of LAMP). Some providers offer Microsoft Windows-based or FreeBSD-based solutions. For example, the Plesk control panel is available for two operating systems, Linux and Windows. Server-side facilities for either OS have similar functionality (for example: MySQL (database) and many server-side programming languages (such as the widely used PHP web programming language) under Linux, or the proprietary SQL Server (database) and ASP.NET programming language under Windows).
There are thousands of shared hosting providers in the United States alone. They range from mom-and-pop shops and small design firms to multi-million-dollar providers with hundreds of thousands of customers. A large portion of the shared web hosting market is driven through pay per click (PPC) advertising or Affiliate programs while some are purely non-profit.
Shared web hosting can also be done privately by sharing the cost of running a server in a colocation centre; this is called cooperative hosting.
Shared web hosting can be accomplished in two ways: name-based and IP-based, although some control panels allow a mix of name-based and IP-based on the one server.
IP-based: In IP-based virtual hosting, also called dedicated IP hosting, each virtual host has a different IP address. The web server is configured with multiple physical network interfaces, or virtual network interfaces on the same physical interface. The web server software uses the IP address the client connects to in order to determine which web site to show the user. The issue of IPv4 address exhaustion means that IP addresses are an increasingly scarce resource, so the primary justification for a site to use a dedicated IP is to be able to use its own SSL certificate rather than a shared certificate.
Name-based: In name-based virtual hosting, also called shared IP hosting, the virtual hosts serve multiple host names on a single machine with a single IP address. This is possible because when a web browser requests a resource from a web server using HTTP/1.1 it includes the requested host name as part of the request. The server uses this information to determine which web site to show the user.