Servers

Server (computing) a server application, operating system, computer, or appliance.
Application server a server dedicated to running certain software applications
Communications server, carrier-grade computing platform for communications networks
Database server provides database services
Proxy server Provides database IT server in services
Fax server provides fax services for clients
File server provides file services
Game server a server that video game clients connect to in order to play online together
Standalone server an emulator for client-server (web-based) programs
Web server a server that HTTP clients connect to in order to send commands and receive responses along with data contents
Client-server a software architecture that separates "server" functions from "client" functions
The X Server part of the X Window System.
Peer-to-peer a network of computers running as both clients and servers