Chapter 3

Help you understand different types of servers commonly found on a network including:◦ File Server◦ Application Server◦Mail Server◦ Proxy Server◦ Print Server◦ Backup Server

Stores user data files.

Network Operating System (NOS) allows accounts to be set up.

Requires username and password.

Can only access your own files.

Stores applications for use across networks.

The application server can be used in two ways:◦ For storing installation files which can easily be deployed

across client machines. Low network traffic but increase in required processing power at

client side.

◦ Allows applications that are installed on the server to be run by client from the server side. High network traffic but less demand on processing at client side.

Manages mail in and out of a network.◦ Checks income emails for viruses◦ Filters out SPAM emails◦ Provides central address book for the organisation◦ Sets email and inbox sizes

Useful for both internal and external email.

Used to cache web pages.

When a request is made to a web server, a web page is downloaded and displayed on the client’s computer. It is also stored or ‘cached’ on the proxy server.

Requests for the same page are then downloaded from a proxy server which is much quicker than downloading from the internet.

Also act as a security buffer.

Clients make a request for a file on a file server.

The proxy intercepts the request and checks the client’s authenticity.◦ Checks validity of user and they have authorisation to

receive a file.

Proxy then requests the file from the file server and forwards it back to the client.

The client never has direct access to the file server.

Allows access to a shared printer.

Usually come with spooler software.◦ Spoolers collect jobs that have been sent to a printer, puts

them in a queue, and then forwards the print queue to the printer.

Printers work much slower than a computer. This is why we use a spool.◦ Computers would slow down if each file was sent to a printer

as the computer would have to wait for the printer to catch up with it.

The backup server backs up all data on the network.

If all users save data on the server, the server can automatically back-up files over night.

This means that if data is lost it can be recovered.◦ It may not be the most up to date version but it is better than

having to start again.

It will usually make use of tape drives.