Why do we need network security?
The aim of network security is to prevent people from accessing the network or parts of it that should be restricted while simultaneously allowing access to the parts people should have access to.
There are 4 areas of network security you need to be familiar with: authentication, encryption, firewalls, and MAC address filtering.
NOTE: This list does not contain antivirus. Probably the most common mistake on a question about network security is for students not to have learned the 4 things they need to discuss and instead try to
talk about antivirus at this point.
Authentication
This refers to the use of a system of usernames and passwords. By having these a network manager can create user access levels so that different users can be given different rights. This allows everyone
to see just the parts of the network that they should. Enforcing sensible rules for passwords is crucial to this. We will learn more about that in the Cyber Security unit.
Encryption
Encryption is where we store some sensitive data in a format that it cannot be read without the key. When data is encrypted, the plaintext goes through an algorithm that uses a key to produce ciphertext.
The ciphertext can only be read with the key which will generally only be provided when a user enters a password to decrypt the file.
Firewalls
A firewall monitors both incoming data to a network and the data leaving it. It has a set of rules to determine what should be let through. This may include denying certain data types, IP addresses or ports of entry
from the internet. A firewall can be either a physical piece of hardware or software based.
MAC address filtering
Each device has a unique MAC address. A MAC address is a 12 hex digit code. MAC addresses can be put on a white list to say only those on this list are allowed on the network or it can be worked the other way with a
black list. This would mean that any MAC address will be accepted unless it is on the black list.