What is the use of firewall in network security? Differentiate IDS and IPS in network security management.

A firewall is a barrier that filters incoming/outgoing traffic by rules, blocking unauthorized access while allowing legitimate mail/web. Can be hardware (in router) or software (Windows Firewall).

Basis	IDS	IPS
Full form	Intrusion Detection System	Intrusion Prevention System
Action	Detects and alerts (like CCTV)	Detects and blocks (like guard)
Placement	Passive, off-path	Inline in traffic path
Example	Alert "port scan from X"	Auto-drop malicious packets

Best practice: firewall + IDS/IPS together — firewall filters known ports, IDS/IPS catches attacks.