34 Questions
What is the primary function of the IPSec component in the network layer?
To add the AH, ESP, or both headers to the payload
Which mode of IPSec is used when security is desired from end to end?
Transport mode
What happens when security is not enabled in the transport layer?
The transport layer packets flow into the network layer
What is the reason for applying ESP first when both AH and ESP are used in transport mode?
Because it is obvious
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
What is the purpose of IPSec in tunnel mode?
To encapsulate an IP packet with IPSec headers and add an outer IP header
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
What is the characteristic of an IKE SA?
It is a duplex connection
What is the purpose of IKE in establishing a VPN?
To negotiate terms and conditions of the communication
What is used to maintain an IKE SA?
A special header and SA identifiers called cookies
What is the characteristic of an IPSec SA?
It is a one-way logical relationship
How many SAs are required for authenticated, confidential, bi-directional communications between systems?
Two
What is the primary purpose of a Security Association (SA)?
To identify and manage the parameters of an IPSec connection
What is the function of the Security Parameters Index (SPI)?
To identify a specific SA in the SA database
What is the purpose of the Authentication Header (AH)?
To authenticate and ensure the integrity of data
What is the format of the Authentication Data field in AH?
96 bits
What is the purpose of the Sequence Number in AH?
To prevent replay attacks
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
What is the purpose of the Encapsulating Security Payload (ESP)?
To encrypt data
What is the format of the ESP header?
Unique format
What is the purpose of the Pad Length field in ESP?
To specify the length of the padding
What is the purpose of the Next Header field in ESP?
To specify the protocol of the encrypted data
What is the primary function of the ESP header in Transport Mode?
To provide integrity and confidentiality of the payload
What is the purpose of the Integrity Check Value in ESP?
To ensure the integrity of the packet
What is the main advantage of ESP over AH?
ESP provides confidentiality, which AH does not
What is the purpose of Internet Key Exchange (IKE)?
To manage IPsec keys and negotiate protocol parameters
What is the name of the protocol that IKE is based on?
ISAKMP and Oakley
What is the current version of IKE?
IKEv2
What is the primary function of ISAKMP?
To create a framework for key exchange
What is the main criticism of IKE?
It is too complex and confusing
What is the purpose of VPNs?
To securely connect multiple private networks across a public network
What is the advantage of using VPNs over leased lines?
VPNs are cheaper
What is the main concern of organizations using VPNs?
Data security
What has driven the evolution of VPNs?
The demand for security features
Learn about the two modes of IPSec, transport mode and tunnel mode, and how they protect IP packets. Understand the differences between ESP and AH protocols in protecting payload and headers.
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