Deep Dive: Firewalls
Part of Prevention Methods · GCSE GCSE Computer Science revision
This deep dive covers Deep Dive: Firewalls within Prevention Methods for GCSE Computer Science. Revise Prevention Methods in 3.6 Fundamentals of Cyber Security for GCSE Computer Science with 19 exam-style questions and 18 flashcards. This topic shows up very often in GCSE exams, so students should be able to explain it clearly, not just recognise the term. It is section 4 of 11 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 11
Practice
19 questions
Recall
18 flashcards
Deep Dive: Firewalls
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
Keep building this topic
Read this section alongside the surrounding pages in Prevention Methods. That gives you the full topic sequence instead of a single isolated revision point.
Practice Questions for Prevention Methods
What is the primary purpose of a firewall?
Explain how penetration testing can improve the security of a network.
Quick Recall Flashcards
19 questions on Prevention Methods — practise free
Instant marking, adaptive difficulty, and 18 spaced repetition flashcards. Free until your GCSEs.
Try PrepWise Free