+ What is a Firewall?
A firewall is a network security device or software that monitors and controls incoming and outgoing traffic based on predefined security rules.
+ Why do we need a Firewall?
- Protect internal networks from threats
- Block unauthorized access
- Control internet usage
- Secure servers and applications
+ Types of Firewalls
- Packet Filtering Firewall
- Stateful Inspection Firewall
- Proxy Firewall
- Next-Generation Firewall (NGFW)
+ Firewall vs ACL
- ACL: Basic traffic filtering on routers
- Firewall: Advanced inspection + security features
Firewalls provide logging, inspection, and threat protection beyond ACLs.
+ Real-World Example
In enterprise and hospital networks, firewalls protect internal servers like HIS, LIS, PACS, and databases from the Internet while allowing controlled access.
+ Common Firewall Mistakes
- Overly permissive rules
- No logging enabled
- Not updating firewall firmware
- Ignoring internal traffic filtering