At which OSI/ISO layer is an encrypted authentication between a client software package and a firewall performed?

The correct answer is C. Transport layer. Encrypted authentication between a client software package and a firewall is performed at the Transport layer (Layer 4). Protocols such as TLS/SSL, which establish encrypted and authenticated channels, operate at this layer. Circuit-level proxy firewalls - which use protocols…

Submitted by katya_ua· Apr 18, 2026Network and Communications Security

Question

Options

ANetwork layer
BSession layer
CTransport layer
DData link layer

How the community answered

(42 responses)

A
2% (1)
B
7% (3)
C
88% (37)
D
2% (1)

Explanation

Encrypted authentication between a client software package and a firewall is performed at the Transport layer (Layer 4). Protocols such as TLS/SSL, which establish encrypted and authenticated channels, operate at this layer. Circuit-level proxy firewalls - which use protocols like SOCKS - also authenticate client connections at Layer 4 before forwarding traffic, without inspecting the application-layer content. This is distinct from packet filtering (Network layer) or application-level gateway inspection (Application layer).

Topics

#OSI Model#TLS/SSL#Network Security Protocols#Authentication

Community Discussion

No community discussion yet for this question.

Full SSCP Practice