FIREWALLS Firewall என்பது computer அல்லது network-க்கு வரும் மற்றும் வெளியே செல்லும் ne……
FIREWALLS
A firewall is a network security system that monitors and controls incoming and outgoing network traffic based on predefined security rules. தமிழில்: ஒரு computer அல்லது network-க்கு: எந்த traffic உள்ளே வரலாம்? எந்த traffic block செய்ய வேண…
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Definition
A firewall is a network security system that monitors and controls incoming and outgoing network traffic base……
Simple Explanation
ஒரு college entrance gate எடுத்துக்கொள்ளுங்கள். Gate-ல் security guard இருக்கிறார். அவர்: Authorized per……
Explanation
Why firewall is needed
Internet-க்கு connected system பல network threats-க்கு exposed ஆகலாம். Firewall: Unauthorized access-ஐ block ……
Flow
Basic firewall flow
Incoming Packet ↓ Firewall ↓ Check Security Rul……
Explanation
Where firewall is placed
Common architecture: Internet ↓ Firewall ↓ Internal Network ↓ Comp……
Explanation
Main functions
Firewall-ன் முக்கிய functions: Traffic Monitoring Packet Filter……
Explanation
1. TRAFFIC MONITORING…
Explanation
Network-க்கு வரும் மற்றும் network-இலிருந்து செல்லும் traffic-ஐ firewall monito……
Explanation
1. PACKET FILTERING…
Explanation
Network communication சிறிய units-ஆக transmit செய்யப்படுகிறது. அவை: Packets Firewall packet informat……
Real Life Example
Example
Firewall rule: Allow TCP Port 443 Blo……
Real Life Example
1. ACCESS CONTROL…
Real Life Example
Firewall ஒரு network security……
Explanation
Example
Employee Network → Allow Serv……
List
1. PORT CONTROL…
Explanation
Port
Network applications/services identify செய்ய port numbers பயன்படுத்தப்படுகின்றன. Exa……
Real Life Example
Example
Allow HTTPS Port 443 Block Te……
Explanation
Firewall rule
Firewall எப்படி decision எடுக்கிறது? Security rules அடிப்படையில். IF Source IP = Trusted Network AND Port = ……
Explanation
Types of firewall
Major firewall types: Packet Filtering Firewall Stateful Inspection Firewall Circu……
Explanation
1. PACKET FILTERING FIREWALL…
Definition
Packet header information பார்த்து allow/block deci……
Flow
Packet ↓ Read Header ↓ Compar……
Explanation
Advantages
Simple Fast Less resource usa……
Explanation
Limitation
Packet content அல்லது complete con……
Explanation
1. STATEFUL INSPECTION FIREWA……
Definition
Individual packet மட்டும் பார்க்காமல் ongoing network connectio……
Simple Explanation
Packet filtering: "இந்த packet என்ன?" Stateful f……
Flow
Packet ↓ Firewall ↓ Check Pack……
Real Life Example
Example
ஒரு user website-க்கு legitimate connection start செய்கிறார். Firewall அந்த conn……
Real Life Example
1. CIRCUIT-LEVEL GATEWAY…
Definition
Network session அல்லது connection legitimate-ஆக establish ஆகிறதா என்பதை monitor ச……
Definition
1. APPLICATION-LEVEL GATEWAY…
Definition
இதனை: Proxy Firewall என்றும் ……
Definition
Application layer-ல் traffic inspect செய்து cli……
Flow
Without Proxy: Client ↓ Internet Server With Proxy Firewall: Client ↓ Proxy ……
Explanation
Advantages
Application-level details inspect செய்ய ம……
Explanation
Limitation
More processing resources தேவ……
Explanation
1. NEXT-GENERATION FIREWALL…
Explanation
NGFW = Next-Generation Firewall Traditional firewall functions-க்கு additional security capabilities சேர்க்கப……
Important
Traditional firewall: IP + Port + Protocol NGFW: IP + Port +……
Important
1. HOST-BASED FIREWALL…
Definition
Individual computer அல்லது de……
Explanation
Example
Laptop └── Host Firewall அந்த specifi……
List
1. NETWORK-BASED FIREWALL…
Definition
Whole network-ஐ protect செய்ய network boundary-ல் deploy செய்யப்படும் fir……
Definition
[HARDWARE vs SOFTWARE FIREWALL] Hardware Firewall Dedicated network device அல்லது……
Explanation
Example
Computer ↓ Software Firewall…
Explanation
Inbound traffic
Outside network-இலிருந்து system/network-க்கு வ……
Explanation
Outbound traffic
Internal system-இலிருந்து external network-க்கு செல்லும் traffic. Computer ↓ Internet இதனை: Outbound Traffic ……
Explanation
Acl
ACL = Access Control List Firewall/router-ல் traffic allow அல்லத……
Explanation
Source ip
Packet எங்கிருந்து வருகிறது என……
Explanation
Destination ip
Packet எங்கு செல்கிறது என்பதை……
Explanation
Protocol
Firewall protocol அடிப்படையில……
Real Life Example
Firewall working example
Suppose office web server HTTPS மட்டும் allow செய்ய வேண்டும். Firewall rules: Allow TCP Port 443 Block Other ……
Real Life Example
Memory Firewall → Traffic Antivirus → Malware [FIREWALL vs IDS] IDS = Intrusion Detection System IDS suspicio……
Explanation
Dmz
DMZ = Demilitarized Zone Public-facing servers-ஐ internal private network-இலிருந்து separate n……
Explanation
Why dmz?
Public web server compromised ஆனாலும் in……
Explanation
Firewall logging
Firewall network activity logs maintain செய்யலாம். Logs contain: Sour……
Explanation
Why logs important?
Firewall logs மூலம்: Suspicious traffic identify செய்ய Securit……
Explanation
Nat and firewall
NAT = Network Address Translation NAT மற்றும் Firewall related concepts ஆனால் same அல்ல. NAT……
Remember
NAT = Address Translation Fir……
Explanation
Firewall limitations
Firewall இருந்தால் 100% cybersecurity கிடைக்காது. Firewall alone எல்லா attacks-ஐ prevent……
Important
Complete security: Firewall + Antivirus + Authenti……
Common Mistake
Common error
Wrong Firewall virus remove செய்கிறது. Correct Firewall pri……
Common Mistake
Common error
Wrong Firewall = Antivirus. Cor……
Common Mistake
Common error
Wrong Firewall incoming traffic மட்டும் பார்க்கும். Correct Fi……
Memory Trick
Firewall functions: M F A B L M……
Explanation
Firewall types memory
P S C A N P - Packet Filtering S - Stateful Inspection ……
TRB Point
TRB / NET / SET examination-க்கு முக்கியமான points: Firewall Controls incoming and outgoing network traffic. ……
Interview Point
Question
What is a firewall? Answer A firewall is a network security system ……
Interview Point
Interview question
What is the difference between a packet-filtering firewall and a stateful firewall? A packet-filtering firewa……
MCQ
A firewall is primarily used ……
MCQ
Which firewall checks source ……
MCQ
Which firewall tracks active ……
MCQ
A firewall commonly operates ……
MCQ
Which type of firewall acts a……
MCQ
NGFW stands for:…
MCQ
Which firewall protects a sin……
MCQ
Which firewall protects a com……
MCQ
Incoming network traffic is k……
MCQ
Traffic leaving a network is:…
MCQ
Which security tool primarily……
MCQ
Which system mainly detects i……
MCQ
IPS stands for:…
MCQ
ACL stands for:…
MCQ
A firewall generally helps en……
Practice
Define Firewall. Why is a firewall required? Explain Packet Filtering Firewall. Explain Stateful Inspection F……
Summary
FIREWALL | ---------------------------- | | | Monitor Filter Control | | | Traffic Rules Allow / Block Major ……
Explanation
Short description
A firewall is a network security mechanism that monitors and controls incoming and outgoing traffic according……
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