Network Servers
A computer on a network that manages network resources. For
example, a file server is a computer and storage device
dedicated to storing files. Any user on the network can store files
on the server.

Application Servers
Also called an appserver. A program that handles all application operations between users and an organization's backend business applications or databases

Web Servers
A computer that hosts (serves up) Web pages.

Print Servers
A print server is a computer that manages printing services for network users.

Backup Servers
Server used to backup all files as a precaution in case the first medium fails

Routers
A device that forwards data packets along networks. A router is connected to at least two networks, commonly LANs and its ISP's network. Routers are located at gateways, the places where two
or more networks connect.

Gateways
A node on a network that serves as an entrance to another network. In enterprises, the gateway is the computer that routes the traffic from a workstation to the outside network that is serving the Web pages.

Firewalls
A system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets.