GSEC · Question #201
On which of the following OSI model layers does IPSec operate?
The correct answer is B. Network layer. IPSec provides security at the Network layer (Layer 3) by encrypting and authenticating IP packets directly.
Question
On which of the following OSI model layers does IPSec operate?
Options
- APhysical layer
- BNetwork layer
- CData-link layer
- DSession layer
How the community answered
(49 responses)- A2% (1)
- B78% (38)
- C6% (3)
- D14% (7)
Why each option
IPSec provides security at the Network layer (Layer 3) by encrypting and authenticating IP packets directly.
The Physical layer deals only with raw bit transmission over hardware media and has no concept of packet-level encryption or authentication.
IPSec operates at the Network layer (OSI Layer 3), where it secures IP packets through protocols like AH (Authentication Header) and ESP (Encapsulating Security Payload). It works at the IP level, meaning security is applied to the packet itself before routing, making it transparent to upper-layer protocols and applications.
The Data-link layer handles MAC addressing and frame delivery on local segments; protocols like L2TP operate here, but IPSec itself works at Layer 3.
The Session layer manages dialog control and session establishment between applications; IPSec does not operate at this layer.
Concept tested: IPSec protocol OSI layer placement
Source: https://learn.microsoft.com/en-us/windows-server/networking/technologies/ipsec/ipsec-overview
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