Types of Network Firewall
Network firewalls wo devices hote hain jo private networks ko unauthorized access se bachane ke liye use kiye jate hain. Firewall ek security solution hota hai jo un computers ya devices ko protect karta hai jo kisi network se connected hote hain. Yeh firewall hardware ya software ke form mein ho sakta hai. Iska main kaam incoming aur outgoing traffic ko monitor aur control karna hota hai, yani wo data jo ek network ke andar aur bahar move kar raha hota hai.
Network firewall ka major purpose inner network ko outer network se separate karna hota hai, taaki inner network secure rahe. Inner network wo network hota hai jo ek organization ke andar create kiya gaya hota hai, jabki outer network wo network hota hai jo inner network ke bahar hota hai, jaise internet. Firewall outer network se aane wale attacks ko rokta hai aur sirf authorized traffic ko hi allow karta hai, is tarah se private network ko secure karta hai.
Packet filtering –>
Definition :
Packet filtering ek network security technique hai jo packets ko unke source IP address, destination IP address, protocol type, aur port numbers ke basis par monitor aur control karti hai. Iska kaam incoming aur outgoing traffic ko predefined rules ke basis par allow ya block karna hota hai.
Example :
Aapke office network me agar ek rule define kiya gaya hai ki sirf port 80 (HTTP) aur 443 (HTTPS) se traffic allow hoga, to koi bhi aur traffic (jaise port 22 ke through SSH access) block ho jayega. Yeh ensure karta hai ki sirf authorized traffic hi network me enter kare.Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- Packet filtering kya hota hai, aur yeh kaunse layer par kaam karta hai?
(Expected Answer: Yeh ek technique hai jo network layer (OSI model ki third layer) par kaam karti hai aur predefined rules ke basis par traffic ko allow ya block karti hai.)
- Packet filtering kya hota hai, aur yeh kaunse layer par kaam karta hai?
Practical Question:
- Aap ek example de kar samjhaayein ki packet filtering kaise kaam karta hai?
(Expected Answer: Mera firewall rule hai ki sirf port 80 aur 443 allow hain. Agar koi packet port 25 par aaye, to wo block ho jayega.)
- Aap ek example de kar samjhaayein ki packet filtering kaise kaam karta hai?
Comparison Question:
- Packet filtering aur stateful firewall me kya difference hai?
(Expected Answer: Packet filtering predefined rules ke basis par har ek packet ko independently evaluate karta hai, jabki stateful firewall session tracking karta hai aur zyada advanced security deta hai.)
- Packet filtering aur stateful firewall me kya difference hai?
Scenario-Based Question:
- Agar aapka network sirf HTTP aur HTTPS traffic allow karta hai, lekin aapko ek internal service ke liye SSH enable karna ho, to kaunsa rule define karenge?
(Expected Answer: Main port 22 (SSH) ke liye ek naya allow rule add karunga, specific source IP ko restrict karte hue.)
- Agar aapka network sirf HTTP aur HTTPS traffic allow karta hai, lekin aapko ek internal service ke liye SSH enable karna ho, to kaunsa rule define karenge?
Stateful inspection –>
Definition :
Stateful inspection firewalls, jine dynamic packet filtering firewalls bhi kehte hain, ek advanced firewall technique hai jo packets ko monitor karte waqt connection ke state ko track karti hai. Yeh ensure karta hai ki packets sirf valid aur trusted sessions ka hissa hain. Agar session established hai, to packets ko allow kiya jata hai; agar nahi, to block kar diya jata hai.
Example :
Maan lijiye, ek client web server se HTTP request bhejta hai (SYN packet ke zariye). Server is request ko accept karta hai aur SYN-ACK response bhejta hai. Yeh session ab “established” state me hai. Agar ab ek attacker random packets bhejta hai bina session ke, to stateful firewall un packets ko block kar dega, kyunki yeh established session ka part nahi hain.
Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- Stateful inspection firewall kya hai aur yeh kaise kaam karta hai?
(Expected Answer: Yeh ek advanced firewall hai jo packets ke saath connection state ko bhi track karta hai. Yeh sirf established sessions ka hissa hone wale packets ko allow karta hai aur unauthorized packets ko block karta hai.)
- Stateful inspection firewall kya hai aur yeh kaise kaam karta hai?
Comparison Question:
- Stateful firewall aur stateless (packet filtering) firewall me kya difference hai?
(Expected Answer: Stateless firewall har packet ko independently evaluate karta hai, jabki stateful firewall session tracking karta hai aur sirf valid connections ko allow karta hai.)
- Stateful firewall aur stateless (packet filtering) firewall me kya difference hai?
Scenario-Based Question:
- Agar ek stateful firewall ke rules define karne ho, to kaunsa default behavior recommend karenge?
(Expected Answer: Default behavior “Deny All” hona chahiye, jisme sirf established aur trusted sessions allow hote hain. Baaki sab ko block kar diya jata hai.)
- Agar ek stateful firewall ke rules define karne ho, to kaunsa default behavior recommend karenge?
Advanced Question:
- Stateful firewall session tracking ke liye kaunsa mechanism use karta hai?
(Expected Answer: Yeh connection table ya state table maintain karta hai, jisme active sessions ke details hote hain, jaise source/destination IPs, port numbers, protocol, aur session ki state (e.g., SYN_SENT, ESTABLISHED).)
- Stateful firewall session tracking ke liye kaunsa mechanism use karta hai?
Key Features for Revision:
- Connection state ko track karta hai (e.g., SYN, SYN-ACK).
- Unauthorized sessions ko block karta hai.
- Packet filtering se zyada secure aur intelligent.
- Stateful firewalls zyada resource-intensive hote hain, lekin better security provide karte hain.
Application layer firewalls –>
Definition :
Application layer firewalls ek advanced firewall type hain jo OSI model ke application layer par kaam karte hain. Yeh firewalls network traffic ko application-specific protocols (e.g., HTTP, SMTP, FTP) ke basis par analyze karte hain aur koi bhi suspicious activity ya malicious application detect hone par communication ko block kar dete hain.
Example :
Maan lijiye, ek organization ka application layer firewall kisi web server par aane wale HTTP requests ko inspect karta hai. Agar koi user ek SQL injection attack attempt kare, to firewall us attack ko detect karke us request ko block kar dega, aur is tarah organization ke web server ko secure rakhega.
Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- Application layer firewall kya hota hai?
(Expected Answer: Yeh ek firewall hai jo application-specific protocols ke traffic ko analyze karta hai aur unke content ko inspect karke unauthorized ya malicious activities ko block karta hai.)
- Application layer firewall kya hota hai?
Comparison Question:
- Packet filtering firewall aur application layer firewall me kya difference hai?
(Expected Answer: Packet filtering firewall sirf source/destination IP aur ports ke basis par traffic ko block/allow karta hai, jabki application layer firewall data packets ke content ko inspect karta hai, jaise HTTP requests ya email content.)
- Packet filtering firewall aur application layer firewall me kya difference hai?
Practical Question:
- Ek web server par SQL injection attacks ko prevent karne ke liye kaunsa firewall use karenge aur kyun?
(Expected Answer: Application layer firewall use karenge, kyunki yeh HTTP requests ke content ko inspect karke malicious payloads (jaise SQL injection) ko detect aur block kar sakta hai.)
- Ek web server par SQL injection attacks ko prevent karne ke liye kaunsa firewall use karenge aur kyun?
Advanced Question:
- Application layer firewalls ka performance aur latency par kya impact hota hai?
(Expected Answer: Detailed content inspection ke kaaran application layer firewalls network latency increase kar sakte hain aur zyada computational resources consume karte hain, lekin yeh higher security provide karte hain.)
- Application layer firewalls ka performance aur latency par kya impact hota hai?
Key Features for Revision:
- OSI model ke application layer par kaam karta hai.
- Application-specific protocols (HTTP, SMTP, FTP) ko inspect karta hai.
- Malicious content ya attacks detect karke block karta hai (e.g., SQL injection, XSS).
- Zyada granular aur effective security provide karta hai compared to traditional firewalls.
- Cons: Latency increase aur high resource utilization.
Is explanation se aapko theoretical understanding ke saath examples aur interview scenarios cover karne me madad milegi.
Next-generation firewalls (NGFW) –>
Definition :
Next-Generation Firewalls (NGFWs) ek advanced type ki firewalls hain jo traditional firewalls ke features jaise packet filtering, stateful inspection, aur application layer filtering ko combine karte hain aur unke upar additional security features provide karte hain, jaise:
- Application awareness and control
- Integrated Intrusion Prevention System (IPS)
- Cloud-delivered threat intelligence
Yeh firewalls real-time me suspicious activities ko detect aur block karne ke liye continuously update hoti hain.
Example :
Maan lijiye, ek enterprise ke NGFW me ek rule set kiya gaya hai ki sirf authorized employees hi cloud storage (e.g., Dropbox) ka use kar sakte hain. NGFW application-level inspection ke zariye Dropbox traffic ko detect karta hai aur unauthorized users ke liye access block kar deta hai. Saath hi, agar kisi traffic me malware detect hota hai, to integrated IPS usse real-time me block kar leta hai.
Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- Next-generation firewall (NGFW) kya hota hai aur yeh traditional firewalls se kaise different hai?
(Expected Answer: NGFW ek advanced firewall hai jo traditional firewalls ke features ke saath application-level control, IPS, aur threat intelligence jaise features provide karta hai. Traditional firewalls se zyada intelligent aur secure hota hai.)
- Next-generation firewall (NGFW) kya hota hai aur yeh traditional firewalls se kaise different hai?
Comparison Question:
- NGFW aur application layer firewall me kya difference hai?
(Expected Answer: Application layer firewall sirf application protocols ko inspect karta hai, jabki NGFW application control ke saath IPS, threat intelligence, aur real-time updates jaise features offer karta hai.)
- NGFW aur application layer firewall me kya difference hai?
Scenario-Based Question:
- Agar ek organization ka network advanced persistent threats (APTs) ka samna kar raha ho, to NGFW kaise help karega?
(Expected Answer: NGFW apne IPS system aur cloud-delivered threat intelligence ke zariye APTs detect kar sakta hai aur real-time me malicious activities ko block kar ke network ko protect karega.)
- Agar ek organization ka network advanced persistent threats (APTs) ka samna kar raha ho, to NGFW kaise help karega?
Practical Question:
- NGFW me application control aur traditional stateful inspection firewall me kya key difference hai?
(Expected Answer: Application control NGFW ko applications identify karne aur specific applications ke behavior par control dene ki ability deta hai, jabki stateful firewalls sirf connection states ko track karte hain.)
- NGFW me application control aur traditional stateful inspection firewall me kya key difference hai?
Key Features for Revision:
- Application awareness and control: Specific applications ko identify aur block/allow karne ki ability.
- Integrated IPS: Real-time intrusion detection aur prevention.
- Cloud-delivered threat intelligence: Threats ke against continuously updated protection.
- High-level security: APTs, malware, aur modern cyber-attacks ke against protection.
- Use Case: Enterprises aur complex networks ke liye ideal.
- Cons: High cost aur resource-intensive.
Circuit-level gateway –>
Definition :
Circuit-Level Gateway ek firewall type hai jo TCP aur UDP connections ki security provide karta hai. Yeh OSI model ke session layer par kaam karta hai aur ensure karta hai ki network me sirf valid aur authenticated connections hi allowed ho. Yeh firewall packets ke content ko inspect nahi karta, balki connection state aur session validity ko verify karta hai.
Example :
Maan lijiye, ek organization ke internal users ko internet par securely communicate karna hai. Circuit-level gateway ek secure session establish karta hai, jisme external users ke liye internal network ke details hide rehti hain. Agar koi unauthorized connection attempt hota hai, to firewall usse block kar deta hai.
Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- Circuit-level gateway kya hota hai aur yeh kaise kaam karta hai?
(Expected Answer: Yeh ek firewall hai jo TCP/UDP connections ko monitor karta hai aur ensure karta hai ki valid sessions hi establish ho. Yeh OSI model ke session layer par kaam karta hai aur data packet ke content ko inspect nahi karta.)
- Circuit-level gateway kya hota hai aur yeh kaise kaam karta hai?
Comparison Question:
- Circuit-level gateway aur packet filtering firewall me kya difference hai?
(Expected Answer: Circuit-level gateway connection state aur session validity ko monitor karta hai, jabki packet filtering firewall packets ko individually inspect karta hai based on source/destination IP aur port numbers.)
- Circuit-level gateway aur packet filtering firewall me kya difference hai?
Scenario-Based Question:
- Agar ek organization ko secure remote communication establish karni ho, to circuit-level gateway kaise help karega?
(Expected Answer: Circuit-level gateway secure sessions establish karega jahan external systems internal network ke details ko directly access nahi kar paayenge. Sirf authenticated connections allow hongi.)
- Agar ek organization ko secure remote communication establish karni ho, to circuit-level gateway kaise help karega?
Advanced Question:
- Circuit-level gateway ka kaunsa limitation hota hai, aur ise overcome karne ke liye kaunsa firewall use karte hain?
(Expected Answer: Circuit-level gateway packets ke content ko inspect nahi karta, isliye application-level attacks ko detect nahi kar sakta. Is limitation ko overcome karne ke liye application-layer firewall use kiya jata hai.)
- Circuit-level gateway ka kaunsa limitation hota hai, aur ise overcome karne ke liye kaunsa firewall use karte hain?
Key Features for Revision:
- OSI Layer: Session layer (between transport and application layers).
- Focus: TCP/UDP connection states aur session validity.
- Inspection: Data content ko inspect nahi karta, sirf connection level security provide karta hai.
- Use Case: Secure communication setup ke liye.
- Limitation: Application-level threats (e.g., malware) ko detect nahi kar sakta.
Software Firewall –>
Definition :
Software Firewall ek computer program hai jo ek system ke andar external attacks aur unauthorized access ko block karne ke liye install aur run kiya jata hai. Yeh firewall incoming aur outgoing data packets ko monitor karta hai aur ensure karta hai ki sirf safe aur authorized traffic hi system tak pahunch paye.
Example :
Aapke laptop me ek software firewall installed hai, jaise Windows Defender Firewall. Jab aap ek insecure website open karte hain ya kisi untrusted application ko internet access chahiye hota hai, firewall aapko warning ya alert deta hai aur connection ko block kar sakta hai, agar wo suspicious ho.
Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- Software firewall kya hota hai aur iska kaam kya hai?
(Expected Answer: Software firewall ek program hai jo system ke data traffic ko monitor karta hai aur unauthorized access aur cyber threats se protection deta hai.)
- Software firewall kya hota hai aur iska kaam kya hai?
Comparison Question:
- Software firewall aur hardware firewall me kya difference hai?
(Expected Answer: Software firewall ek program ke roop me system par run karta hai, jabki hardware firewall ek dedicated device hota hai jo network level par security provide karta hai.)
- Software firewall aur hardware firewall me kya difference hai?
Scenario-Based Question:
- Agar kisi system me suspicious outgoing connections detect ho rahe ho, to software firewall kaise madad karega?
(Expected Answer: Software firewall suspicious connections ko block kar dega aur user ko alert karega, jisse user un applications ko disable kar sake jo malicious behavior show kar rahi hain.)
- Agar kisi system me suspicious outgoing connections detect ho rahe ho, to software firewall kaise madad karega?
Advanced Question:
- Software firewalls ke kuch limitations kya hain?
(Expected Answer: Software firewalls system resources consume karte hain, aur network-wide security provide karne me limited hote hain. Yeh sirf individual system ko protect karte hain.)
- Software firewalls ke kuch limitations kya hain?
Key Features for Revision:
- Location: System-level par install aur run hota hai.
- Function: Incoming/outgoing traffic ko monitor karta hai aur unauthorized access block karta hai.
- Alert System: Suspicious activities ke liye user ko warn karta hai.
- Use Case: Personal devices aur standalone systems ke liye ideal.
- Limitation: High resource consumption aur network-wide protection provide nahi karta.
Hardware Firewall –>
Definition :
Hardware Firewall ek dedicated physical device hai jo network boundary par deploy kiya jata hai. Yeh inbound aur outbound traffic ko monitor karta hai aur predefined security policies ke basis par unauthorized access aur potential threats ko block karta hai. Iska main kaam network-wide protection provide karna hai.
Example :
Maan lijiye, ek organization apne corporate network aur internet ke beech ek hardware firewall (e.g., Cisco ASA, Fortinet) install karti hai. Jab bhi koi user internet se organization ke network me connect karne ki koshish karta hai, firewall uske traffic ko inspect karta hai aur malicious traffic ko block kar deta hai, sirf authorized requests ko allow karta hai.
Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- Hardware firewall kya hota hai aur iska kaam kya hai?
(Expected Answer: Hardware firewall ek physical device hai jo network boundary par inbound aur outbound traffic ko monitor karta hai aur unauthorized access aur malicious activities ko block karta hai.)
- Hardware firewall kya hota hai aur iska kaam kya hai?
Comparison Question:
- Hardware firewall aur software firewall me kya difference hai?
(Expected Answer: Hardware firewall ek dedicated physical device hai jo network-wide protection provide karta hai, jabki software firewall ek program hai jo ek single system par run hota hai aur usi system ko protect karta hai.)
- Hardware firewall aur software firewall me kya difference hai?
Scenario-Based Question:
- Ek large enterprise apne network ke liye hardware firewall kyu prefer karega?
(Expected Answer: Hardware firewall large enterprises ke liye better hai kyunki yeh high-performance traffic monitoring aur multiple devices ke liye network-wide protection provide karta hai. Yeh heavy traffic ko efficiently handle kar sakta hai.)
- Ek large enterprise apne network ke liye hardware firewall kyu prefer karega?
Advanced Question:
- Hardware firewall ke kuch limitations kya hain?
(Expected Answer: Hardware firewalls costly hote hain, aur unki configuration aur maintenance ke liye skilled professionals ki zarurat hoti hai. Mobile users ke liye protection limited hoti hai.)
- Hardware firewall ke kuch limitations kya hain?
Key Features for Revision:
- Location: Network boundary par deploy hota hai.
- Function: Inbound/outbound traffic ko inspect aur block/allow karta hai.
- Use Case: Large networks aur enterprises ke liye ideal.
- Benefits: High-performance security aur network-wide protection.
- Limitation: High cost, complexity in configuration, aur mobile devices ke liye limited protection.
Cloud Firewall –>
Definition :
Cloud Firewall ek software-based firewall hai jo cloud environments me deploy kiya jata hai aur network ko unauthorized access aur malicious attacks se protect karta hai. Yeh traditional hardware firewalls ke opposite, cloud level par data filtering aur monitoring karta hai aur scalability aur flexibility provide karta hai.
Example :
Maan lijiye, ek company apne web applications ko AWS (Amazon Web Services) par host karti hai. Cloud firewall (e.g., AWS WAF – Web Application Firewall) malicious traffic ko detect karta hai, jaise SQL injection ya DDoS attacks, aur automatically unhe block kar deta hai. Saath hi, yeh company ke dynamic traffic requirements ke according scale ho jata hai.
Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- Cloud firewall kya hota hai aur yeh kaise kaam karta hai?
(Expected Answer: Cloud firewall ek software-based firewall hai jo cloud environment ke traffic ko monitor karta hai aur unauthorized access aur malicious activities ko block karta hai.)
- Cloud firewall kya hota hai aur yeh kaise kaam karta hai?
Comparison Question:
- Cloud firewall aur hardware firewall me kya difference hai?
(Expected Answer: Cloud firewall software-based hota hai aur cloud environments me deploy hota hai, jabki hardware firewall ek physical device hai jo on-premises networks ke liye kaam karta hai. Cloud firewalls scalability aur flexibility offer karte hain.)
- Cloud firewall aur hardware firewall me kya difference hai?
Scenario-Based Question:
- Agar ek organization ka infrastructure completely cloud-based hai, to wo hardware firewall ki jagah cloud firewall kyu choose karega?
(Expected Answer: Cloud firewall directly cloud services ke sath integrate hota hai, aur infrastructure ke scale hone par automatically scale ho jata hai. Iske liye on-premises hardware ki zarurat nahi hoti.)
- Agar ek organization ka infrastructure completely cloud-based hai, to wo hardware firewall ki jagah cloud firewall kyu choose karega?
Advanced Question:
- Cloud firewall ke kuch benefits aur limitations kya hain?
(Expected Answer: Benefits me flexibility, scalability, aur cost-effectiveness aata hai. Limitations me complete reliance on internet connectivity aur latency issues ho sakte hain.)
- Cloud firewall ke kuch benefits aur limitations kya hain?
Key Features for Revision:
- Location: Cloud environments me deploy hota hai.
- Function: Cloud-based traffic ko monitor karta hai aur unauthorized access ko block karta hai.
- Use Case: Cloud-hosted applications aur services ke liye ideal.
- Benefits:
- Scalability: Dynamic traffic requirements handle karna.
- Integration: Cloud services ke sath seamless integration.
- Flexibility: Hardware ki dependency nahi hoti.
- Limitations:
- Internet dependency ke wajah se latency aur connectivity issues.
- Cloud service providers ki security ke upar depend rehna.
WAF (Web Application Firewall) –>
Definition :
WAF (Web Application Firewall) ek specialized firewall hai jo web applications ko HTTP aur HTTPS traffic ko filter karke protect karta hai. Yeh common web attacks, jaise SQL Injection, Cross-Site Scripting (XSS), aur Cross-Site Request Forgery (CSRF), ko detect aur block karta hai, aur web applications ki security ko ensure karta hai.
Example :
Agar ek e-commerce website par SQL injection attack hone ki koshish ki ja rahi ho, to WAF incoming HTTP requests ko analyze karega. Agar usme malicious payload detect hota hai, to WAF us request ko block kar dega aur application ko hack hone se bacha lega. AWS WAF ya Cloudflare WAF iske popular examples hain.
Kaise Interview Me Puchha Jaa Sakta Hai?
Basic Question:
- WAF kya hota hai aur yeh kaise kaam karta hai?
(Expected Answer: WAF ek web application-specific firewall hai jo HTTP aur HTTPS traffic ko monitor karta hai aur web-based attacks ko block karta hai.)
- WAF kya hota hai aur yeh kaise kaam karta hai?
Comparison Question:
- WAF aur traditional firewalls me kya difference hai?
(Expected Answer: WAF application-layer (HTTP/HTTPS) traffic ko filter karta hai aur web-based vulnerabilities (e.g., SQL injection, XSS) ko target karta hai. Traditional firewalls network-level security dete hain aur web-specific attacks detect nahi kar paate.)
- WAF aur traditional firewalls me kya difference hai?
Scenario-Based Question:
- Ek organization ko WAF ki zarurat kyu padti hai, jab unke paas already ek hardware firewall hai?
(Expected Answer: Hardware firewall network-level threats (e.g., unauthorized access, DDoS attacks) ko block karta hai, lekin WAF web application-specific vulnerabilities (e.g., CSRF, XSS) ko target karta hai, jo hardware firewall nahi kar sakta.)
- Ek organization ko WAF ki zarurat kyu padti hai, jab unke paas already ek hardware firewall hai?
Advanced Question:
- WAF ka kaam hone ke bawajood, application vulnerabilities ka risk kyun hota hai?
(Expected Answer: WAF application vulnerabilities ko mitigate karta hai, lekin agar WAF ki policies ya configurations weak hain, ya naye attack vectors use ho rahe hain jo WAF ke detection scope ke bahar hain, to vulnerabilities ka risk reh sakta hai.)
- WAF ka kaam hone ke bawajood, application vulnerabilities ka risk kyun hota hai?
Key Features for Revision:
- Layer: OSI Model ka Application Layer (HTTP/HTTPS traffic ko inspect karta hai).
- Protection Against:
- SQL Injection
- Cross-Site Scripting (XSS)
- Cross-Site Request Forgery (CSRF)
- Malicious Bots aur Zero-Day Exploits
- Use Case: Business websites, e-commerce platforms, aur APIs ke liye zaruri hai.
- Deployment Options: Cloud-based aur on-premises solutions available hain.
- Advantages:
- Granular protection against web vulnerabilities.
- Scalability aur integration with existing infrastructure.
- Limitations:
- High setup cost aur complex configuration.
- Advanced attacks ke liye continuous updates ki zarurat.
