Network Security and Threats

Firewall use

Used to prevent unauthorised access to a network.

What does a firewall consist of

two NICs between the user and the internet

How does a firewall work

The firewall passes the packets between the two NICs and compares them against a set of rules set by the firewall software.

What are the set of firewall rules called

Packet filters

What does packet filtering / static filtering do

limits network access in accordance with administrator rules and policies. Examines the source IP, destination IP and the protocols being used, as well as the ports being requested.

What happens when access is denied by a firewall

Packet can either be dropped or rejected

Difference between dropped packet and rejected packet

A rejected packet sends an alert to the sender to notify them of the error whereas a dropped packet will not

Proxy server

Acts as an intermediary, collecting and sending data on behalf of a user

Benefits of a proxy

Privacy of user protected, can cache frequently used website data making it faster to load, reduce overall web traffic, can be used by admins to prevent access to sensitive information at work or school

Encryption

Makes data unreadable if it is intercepted. Encrypted and decrypted using keys