Software firewalls work at which layer of the OSI model?

The correct answer is B. Application. Software (host-based) firewalls, especially application-layer or next-generation firewalls, operate at Layer 7 (Application) of the OSI model. This allows them to inspect actual application-level traffic - understanding protocols like HTTP, FTP, DNS, and SMTP - and make…

Submitted by kevin_r· Apr 18, 2026Network Forensics

Question

Options

ATransport
BApplication
CData Link
DNetwork

How the community answered

(31 responses)

B
94% (29)
C
3% (1)
D
3% (1)

Explanation

Software (host-based) firewalls, especially application-layer or next-generation firewalls, operate at Layer 7 (Application) of the OSI model. This allows them to inspect actual application-level traffic - understanding protocols like HTTP, FTP, DNS, and SMTP - and make filtering decisions based on content, not just ports and IP addresses. This is more granular than packet-filtering firewalls (Layer 3/Network) or stateful firewalls (Layer 4/Transport). The ability to inspect application data is what allows software firewalls to block specific applications, URLs, or content types.

Topics

#OSI model#Software firewalls#Network security#Firewall operation

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