Client-server networks became more popular in the 1990s, when personal computers became the alternative to mainframe computers. Client-server networks refer to a computer networking model that uses both client hardware devices and servers, each with specific functions.

The client-server model can be used both on the Internet and on a local area network (LAN). Examples of client-server systems on the Internet are web browsers and web servers, FTP clients and servers, and DNS.

Client devices are typically PCs with network software applications installed that request and receive information over the network. In addition, mobile devices function as clients.

Servers store files and databases, including complex applications and websites. Servers typically have more powerful central processors, more memory, and larger disks than client devices.