In short
A firewall is a network security device or program that filters incoming and outgoing traffic according to rules, allowing approved traffic and blocking the rest.
Key takeaways
- It is a preventive control at network boundaries and between internal network segments.
- Rules should deny by default and be reviewed regularly.
- It doesn't stop attacks carried in allowed traffic, such as phishing emails.
Where it's tested
ISC: Information Security Fundamentals — study notes, a five-minute revision sheet and practice questions.
Practise: 3 questions
Question 1 of 3 · 0 answered
A company protects its systems with firewalls, multi-factor authentication, encryption, endpoint protection and employee training, so that one failed control does not expose everything. This approach is called: