What is a firewall?
A firewall is a security system that uses a set of predetermined rules to analyse and control the traffic that comes in and goes out of your network.
Give a real world analogy of how a firewall works
Think of it like a bouncer at a bar. It keeps unsafe traffic out, while allowing anything legitimate to pass through without an issue.
Firewalls can implement security rules. Give an example of one that a company might implement.
Out of the 500 computers inside this company, only one of them is permitted to receive public FTP traffic. Allow FTP connections only to that one computer and prevent them on all others.
What are the 3 main types of firewall technique?
- Proxy Server
- Circuit-level gateway
- Packet filter
What does a proxy server do?
- Checks all messages entering and leaving the network
2. Hides the true network addresses of the hosts
What is a circuit-level gateway used for?
TCP connections
How do circuit-level gateways work?
- They monitor TCP handshaking to determine whether a requested session is legitimate
- On establishment of that secure, legitimate connection, data packets can flow between the hosts without further checking
At what layer of the OSI model do circuit level gateways work?
Circuit-level gateways work at the session layer of the OSI model, or as a “shim-layer” between the application layer and the transport layer of the TCP/IP stack.
What’s the difference between basic firewalls and more effective ones?
Basic firewalls only monitor incoming traffic by default. An effective firewall monitors both incoming and outgoing traffic.
What are the two types of firewall?
Hardware and software
What is a hardware firewall?
A router or any other security product that is placed between the network and the outside world.
Describe a software firewall
- installed on the device
- will deflect incoming attacks and hide open ports.
- will give warning about suspicious outgoing traffic.
- possible to have a software firewall on each computer for strong protection.
- By installing software firewall, an attacker will have to cross two levels of security to access your device (the second being the hardware firewall).
