SERVER
In computer networking, a server is
a computer designed to process requests and deliver data to other (client)
computers over a local network or the Internet.
Network servers typically are configured with
additional processing, memory, and storage capacity to handle the load of
servicing clients. Common types of network servers include:
- Web
servers
- Proxy
servers
- FTP
servers
- Online
game servers
Numerous systems on the Internet employ this client-server networking model including Web sites and email services.
An alternative model – peer-to-peer networking – enables all devices on a network to function as either a server or client as needed.
Server Clusters:
The word cluster is used broadly in computer networking
to refer to a number of different implementations of shared computing
resources. Typically, a cluster integrates the resources of two or more
computing devices that could otherwise function separately (often, workstation
or server devices) together for some common purpose.
Web servers:
A Web server farm (a collection of networked
Web servers, each with access to content on the same site) function as a
cluster conceptually. However, purists can debate the technical classification
of a server farm as a cluster, depending on the details of the hardware and
software configuration (failover characteristics, etc.).
Proxy Servers:
Proxy servers work as an intermediary between the two ends of a client/server network connection.
Proxy servers interface with network applications, most commonly Web browsers and servers. Inside corporate networks, proxy servers are
installed on specially-designated internal (intranet) devices. Some Internet Service Providers
(ISPs) also utilize proxy servers as part of providing online
services to their customers.
Finally, a category of third-party hosted Web sites called Web proxy servers is available to end users on the Internet for their Web browsing sessions.
Key Features of Proxy Servers
Proxy servers traditionally
provide three main functions:
- firewall
and network data filtering support
- network
connection sharing
- data
caching
FTP server:
The File Transfer Protocol (FTP) is a standard network protocol used to transfer computer files between a client and server on a computer
network.
FTP is built on a client-server
model architecture and uses separate control and data connections between the
client and the server. FTP users may authenticate themselves with a clear-text sign-in protocol, normally in the form
of a username and password, but can connect anonymously if the server is
configured to allow it. For secure transmission that protects the username and
password, and encrypts the content, FTP is often secured with SSL/TLS (FTPS). SSH File Transfer Protocol (SFTP) is sometimes also used instead,
but is technologically different.
The first FTP client applications
were command-line programs developed before operating systems had graphical
user interfaces, and are still shipped with most Windows, Unix, and Linux operating systems. Many FTP clients
and automation utilities have since been developed for desktops, servers,
mobile devices, and hardware, and FTP has been incorporated into productivity
applications, such as web page
editors.