Firewall Facts you must know for the CISSP exam!
Firewalls have made up a popular subject of study for a long time now. The CISSP expects you to understand the advantages and disadvantages of different types of firewalls. It also tests your ability to suggest a type of firewall given a scenario, analysing the trade off between security and performance.
The Purpose of Firewalls:
They maintain the routing rules .
Act as a single choke point (all traffic must pass through the firewall).
Allow only authorised traffic (accept/ deny rules are applied on both inbound and outbound traffic).
Enforce immunity against penetration attacks.
Firewall Limitations:
Ineffective against attacks that bypass the firewalls (e.g. you can access the internet without connecting to the office VPN, thereby bypassing corporate firewall).
Viruses and malwares could compromise the integrity of the firewall rules and hence the effectiveness of the firewall itself.
Types of Firewalls (More details later):
Packet Filtering Router firewalls.
Proxy firewalls.
Stateful Inspection firewalls.
Types of Firewall Implementations (including placements):
Single Homed Bastion Host
Dual Homed Bastion Host
Demilitarised firewall (also known as Screened Subnet firewall)