This deep dive covers Deep Dive: Firewalls within Prevention Methods for GCSE Computer Science. Revise Prevention Methods in Network Security for GCSE Computer Science with 15 exam-style questions and 18 flashcards. This topic appears less often, but it can still be a useful differentiator on mixed-topic papers. It is section 4 of 10 in this topic. Use this deep dive to connect the idea to the wider topic before moving on to questions and flashcards.
Topic position
Section 4 of 10
Practice
15 questions
Recall
18 flashcards
Deep Dive: Firewalls
How Firewalls Protect Networks
A firewall sits between your internal network and the external Internet, acting as a security checkpoint.
How it works:
- Monitors traffic: Inspects all incoming and outgoing network packets
- Applies rules: Uses predefined rules to decide whether to allow or block traffic
- Filtering criteria:
- Source IP address: Where is traffic coming from?
- Destination IP address: Where is it going?
- Port number: What service is being accessed? (e.g., port 80 = HTTP)
- Protocol: TCP, UDP, ICMP, etc.
- Action: Allow (permit traffic) or Deny (block traffic)
Example firewall rules:
- Allow: HTTP traffic (port 80) from any source to web server
- Allow: HTTPS traffic (port 443) from any source to web server
- Deny: All SSH traffic (port 22) from external sources
- Deny: All other traffic by default