IPSec Modes and Protocols

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What is the primary function of the IPSec component in the network layer?

To add the AH, ESP, or both headers to the payload (correct)
To authenticate the data link layer packets
To make routing decisions for packets flowing through a router
To encrypt the IP header

Which mode of IPSec is used when security is desired from end to end?

Transport mode (correct)
Tunnel mode
Network mode
Envelope mode

What happens when security is not enabled in the transport layer?

The transport layer packets are authenticated
The transport layer packets are encrypted
The transport layer packets flow into the network layer (correct)
The transport layer packets are blocked

What is the reason for applying ESP first when both AH and ESP are used in transport mode?

Because it is obvious (D) Signup and view all the answers

What is the primary difference between tunnel mode and transport mode?

Tunnel mode protects the entire IP packet, while transport mode protects only the payload (A) Signup and view all the answers

What is the purpose of IPSec in tunnel mode?

To encapsulate an IP packet with IPSec headers and add an outer IP header (D) Signup and view all the answers

Why can't transport mode IPSec header be inserted for packets flowing through a router?

Because it violates the rule of routers looking only at the network layer header (D) Signup and view all the answers

What is the characteristic of an IKE SA?

It is a duplex connection (A) Signup and view all the answers

What is the purpose of IKE in establishing a VPN?

To negotiate terms and conditions of the communication (C) Signup and view all the answers

What is used to maintain an IKE SA?

A special header and SA identifiers called cookies (D) Signup and view all the answers

What is the characteristic of an IPSec SA?

It is a one-way logical relationship (B) Signup and view all the answers

How many SAs are required for authenticated, confidential, bi-directional communications between systems?

Two (B) Signup and view all the answers

What is the primary purpose of a Security Association (SA)?

To identify and manage the parameters of an IPSec connection (B) Signup and view all the answers

What is the function of the Security Parameters Index (SPI)?

To identify a specific SA in the SA database (C) Signup and view all the answers

What is the purpose of the Authentication Header (AH)?

To authenticate and ensure the integrity of data (B) Signup and view all the answers

What is the format of the Authentication Data field in AH?

96 bits (C) Signup and view all the answers

What is the purpose of the Sequence Number in AH?

To prevent replay attacks (B) Signup and view all the answers

What is the difference between tunnel mode and transport mode in IPSec?

Tunnel mode encrypts the entire IP packet, while transport mode only encrypts the payload (C) Signup and view all the answers

What is the purpose of the Encapsulating Security Payload (ESP)?

To encrypt data (D) Signup and view all the answers

What is the format of the ESP header?

Unique format (A) Signup and view all the answers

What is the purpose of the Pad Length field in ESP?

To specify the length of the padding (A) Signup and view all the answers

What is the purpose of the Next Header field in ESP?

To specify the protocol of the encrypted data (C) Signup and view all the answers

What is the primary function of the ESP header in Transport Mode?

To provide integrity and confidentiality of the payload (C) Signup and view all the answers

What is the purpose of the Integrity Check Value in ESP?

To ensure the integrity of the packet (D) Signup and view all the answers

What is the main advantage of ESP over AH?

ESP provides confidentiality, which AH does not (A) Signup and view all the answers

What is the purpose of Internet Key Exchange (IKE)?

To manage IPsec keys and negotiate protocol parameters (C) Signup and view all the answers

What is the name of the protocol that IKE is based on?

ISAKMP and Oakley (D) Signup and view all the answers

What is the current version of IKE?

IKEv2 (C) Signup and view all the answers

What is the primary function of ISAKMP?

To create a framework for key exchange (A) Signup and view all the answers

What is the main criticism of IKE?

It is too complex and confusing (A) Signup and view all the answers

What is the purpose of VPNs?

To securely connect multiple private networks across a public network (A) Signup and view all the answers