Learning Resources
Lesson
There is often confusion around the terms server and client. Both servers and clients may be
- Hardware. A computer set up for the exclusive purpose of providing network user accounts, file storage and/or printer services is generally referred to as a server. A computer set up for use by an individual is generally called a workstation.
- An operating system. Servers generally run network operating systems such as Windows 2000 Server, Unix, or Linux server. Workstations generally run software such as Windows 98, 2000 Personal or Professional, Windows XP home or Professional. The Mac OS, which is now Unix based has both client (workstation) versions and server versions. Linux and Unix workstations are widely used in industry to run high end graphics applications.
- Software. All computers run an operating system. It provides the framework for all the layers from layer 3 up. Applications can only run inside and operating system They rely on the operating systems for file management and all other services. With respect to networking, there are server applications and client applications. This section will look at several internet-based server and client applications.
Any computer can run client software. Any computer can run server software. Server software is independent of the operating system. For example, any computer can be a web server, if web server software is installed.
If you recall, networks keep track of computers identities and 'place' on the network by assigning them IP addresses. www.cdli.ca for example lives at 134.153.233.1
Server software running on a computer is uniquely identified to the network by the port it makes available. Think of ports as doors. A computer has approximately 65,000 ports available. By agreement, some applications are assigned a specific port number regardless of the computer it is running on.
It is worth noting that opening ports on a computer makes it vulnerable to hackers, viruses, Trojan horses and worms. By default, Windows computers have all ports open, making them quite easy to get infected. Computers that live on a network that uses a firewall will not be able to use server software that requires open ports unless the ports are opened in the firewall. Networks that use a broadband router, for example, are generally protected because all the ports are closed to the internet in the router unless you specifically open them and designate which computer on the network will be using them. In this regard, a broadband router acts like a hardware firewall protecting the network from everything except the people who use it. They can of course download stuff or open infected email.
Activity
Please complete all activities
- Compile a database of available network and client hardware (computers)
- Compile a database of available network and client operating systems (there are more than you think)
- Create a portfolio entry
- Publish the entry to your course portfolio web
Test Yourself
There is no self test for this lesson.