Interview Questions.

Network Security Interview Questions and Answers


Network Security Interview Questions and Answers

Q1. What are the distinct layers of OSI?


Data link layer

Transport layer

Application layer

Session layer

Data link layer

Presentation layer

Q2. What is intranet?

Ans: It is a private network primarily based on TCP/IP protocols accessible only via the organization’s individuals or a person with authorization

Q3. What is Data encryption?

Ans: Data encryption guarantees information safety and really crucial for personal or important records. It guard records from being examine, altered or forged even as transmission.

Q4. What is the distinction between VPN and VLAN?

Ans: VPN: Creating a secured tunnel of communique over internet to a far off host.

VLAN: Sub department of a community, commonly achieved for mapping hosts of identical department

Q5. Which layers are referred as network assist layers?


Data hyperlink layer

Physical layer

Network layer

Q6. What is RIP?

Ans: RIP stands for Routing Information Protocol, is a simple protocol used to exchange information among the routers.

Q7. What is supposed via port blockading inside LAN ?

Ans: Port blocking is preventing the source to no longer to get entry to the vacation spot node through ports as application works at the ports so ports are blocked to restricts the get entry to  filling up the safety holes in the network infrastructure. Blocking may be performed on the firewall & on a router itself via an ex. Acl.

Q8. What are the differences among encoding, encryption and hashing?

Ans: Encoding: Basically encoding is used to guard the integrity of facts because it crosses through conversation community to maintain its authentic message upon arriving. It is often an insecure feature because it is easily reversible.

Encryption: Encryption is basically designed for confidentiality and information integrity and reversible most effective if you have the proper key

Hashing: With hashing the operation is one-way i.E. Non-reversible. It takes an input (or ,message ) and returns a set-size string, that is called the hash fee.

Q9. Which protocols uses utility layer?






Q10. Difference among routing protocol and routed protocol?

Ans: Routed protocols are the protocols that used with in most cases Application, Presentation layers .. And many others in other words they address your os device and the way your PC , Ip telephone ... And so on will get hold of the data.

Routing protocols are the protocols which might be utilized by the routers to speak with every others like OSOP, RIP , EIGRP , ISIS ... And many others

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Q11. What are the elements that have an effect on the performance of the network?


Type of transmission media


Number of users


Q12. Name the styles of mistakes?

Ans: There are two forms of mistakes:

Single bit mistakes

Burst errors

Q13. What are Brute Force Attacks?

Ans: Brute forcing is a mechanism that is used by an attacker to interrupt the encryption of information by applying a hard and fast of diverse key. Cryptanalyst has a hard and fast of quantity of keys and observe them one after the other to the encryption set of rules till he get the right key.

Example: http://www.Abc.Com/online/Displaymsg.Asp?MsgID=87951

Q14. In An Icmp Address Mask Request, What Is The Attacker Looking For?

Ans: The attacker is seeking out the subnet/network masks of the sufferer. This would help the attacker to map the inner community.

Q15. How do you operate RSA for each authentication and secrecy?

Ans: RSA is a public key encryption algorithm. The RSA algorithms are based totally at the mathematical part that it is straightforward to find and multiply big top numbers together, however it's miles extraordinarily tough to thing their product.For authentication: One can encrypt the hash (MD4/SHA) of the facts with a personal key. This is referred to as virtual signature.

For Secrecy: Secrecy/confidentiality is carried out by using encrypting the facts with public key and decrypting with non-public key.

Q16. Which Feature On A Network Switch Can Be Used To Protect Against Cam Flooding Attacks?

Ans: Port-Security function may be used for the same. In a cam flooding attack, the attacker sends a storm of mac-addresses (frames) with unique values. The intention of the attacker is to top off the cam table. Port-Security can be used to limit the number of mac-addresses allowed at the port.

Q17. What is Authentication Header and how it affords the safety to IP header?

Ans: Basically Authentication Header protects IP header and provides the complete authenticity to the IP packets.AH may work in  methods: transport mode and tunnel mode.

In tunnel mode; AH protects the IP header using two IP header layers inner and outer. Inner IP header is used to comprise the source and destination addresses, and the outer IP header is used to comprise the security gateway statistics.

Q18. What is the Public Key Encryption?

Ans: Public key encryption use public and personal key for encryption and decryption. In this mechanism, public secret's used to encrypt messages and simplest the corresponding private key can be used to decrypt them. To encrypt a message, a sender has to realize recipient’s public key.

Q19. What is Digital Signatures ?

Ans: Digital signature is an attachment to an electronic mail used for protection purpose. It is used to verify the authenticity of the sender

Q20. Which Protocol Does Https Uses At The Transport Layer For Sending And Receiving Data?

Ans: TCP

Q21. What does CIA stand for in protection management?

Ans: Confidentiality, integrity and availability, additionally referred to as the CIA triad, is a version designed to guide regulations for information security within an enterprise. The version is likewise occasionally called the AIC triad (availability, integrity and confidentiality) to keep away from confusion with the Central Intelligence Agency

Q22. What Is A Firewall?

Ans: A Firewall is software that blocks unauthorized customers from connecting on your pc. All computer systems at Bank Street are covered by a firewall that is monitored and up to date through CIS.

Q23. Why Does Active Ftp Not Work With Network Firewalls?

Ans: When a user initiates a connection with the FTP server,  TCP connections are set up. The second TCP connection (FTP statistics connection) is initiated and mounted from the FTP server. When a firewall is between the FTP client and server, the firewall might block the connection initiated from the FTP server on the grounds that it is a connection initiated from outdoor. To clear up this, Passive FTP can be used or the firewall rule may be changed to feature the FTP server as relied on.

Q24. What Is A Sid (security Id)?

Ans: SID stands for Security Identifier and is an internal fee used to uniquely identify a consumer or a set. A SID incorporate * User and group safety descriptors * 48-bit ID authority * Revision level * Variable sub authority values

Q25. What Is Administrator Privileges When Trying To Install A Download?

Ans: Administrator privileges permits the user full get right of entry to to a application or network 2nd simplest to the system account. If you do not have administrator privileges, you cannot do sure matters You may be capable use a program, however not improve it.

Q26. Can Police Track An Ip Address After It Has Been Changed?

Ans: Sometimes-as an example, if the person has a dynamic IP deal with, and their IP address changes within this system as usual, it can generally be tracked. If the person makes use of a proxy carrier to make their IP deal with seem like it's miles located in some random other p

Q27. How Did Early Computer Security Work?

Ans: It changed into quite simple- simply passwords to guard one's laptop. With the innovation of the internet, but, computers have elevated protection with firewalls and hundreds of anti-virus packages.