Which Traffic Flow Should Be Isolated Inside an Internal Firewall?
Short answer
A East-west
Question
Key Takeaways
The exam tests whether you understand that east-west traffic is internal between systems, and the common trap is choosing north-south because it involves servers, but those servers are within the same internal trust zone.
East-west traffic must be isolated when segmenting internal network traffic between devices, servers, and users. Most candidates correctly identify A (east-west), since north-south traffic refers to flows that enter or leave the network perimeter.
Common mistake: D. North-south – this is the popular wrong answer because candidates associate server communication with inbound/outbound traffic; however, the question specifies an internal firewall and traffic between internal roles, which is east-west.
Expert Analysis
Why the Answer Is Correct
East-west traffic refers to data moving between devices, servers, and users within the same data center or internal network — exactly what the question describes. Isolating this lateral traffic with an internal firewall prevents an attacker who compromises one internal asset from freely moving to others. This is a core zero-trust concept: the internal firewall is used to segment east-west communication, not just filter external boundary traffic.
Why the Other Options Are Wrong
North-south traffic (D) is ingress/egress traffic between the internal network and external networks, such as data entering from or leaving to the internet — not the internal flows described. Access/edge (B) and core/distribution (C) refer to hierarchical network layers (Cisco-style architecture), not to traffic-flow directions. Therefore, A is the only option that matches the scenario of isolating internal east-west traffic.
Community Comment Notes
Community commenters overwhelmingly supported A, with one simply stating, "If it's internal it's east west guys" and another explaining that north-south is only for external networks and servers. A few voters chose D, with one arguing that "servers usually exist one level up from users," but this confuses logical hierarchy with traffic-flow terminology. Another commenter noted that server-to-client communication is north-south, but that applies to traffic crossing the datacenter boundary, not to segmentation among internal systems.
Official Reference
https://www.comptia.org/certifications/network
This link opens the official vendor documentation in a new tab.
Exam Strategy
Memorize the two traffic-flow terms: east-west = internal/lateral traffic between servers, devices, and internal users; north-south = traffic entering or leaving the network/data center. When the question stresses "internal firewall" or "inside the network," always choose east-west — even if servers or clients are mentioned.
Community Votes
77% of anonymous learners picked answer A. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 7 contributions
Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.
From public community threads 7
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a87d6a4 👍 3 Answered AThis is the correct answer because east-west traffic refers to the movement of data packets between devices or servers within the same data center or network, such as between servers or between virtual machines. Isolating east-west traffic helps to prevent unauthorized access and improve security within the internal network by ensuring that only specific devices or servers can communicate with each other. B. Access/edge refers to the flow of data between end-user devices and the network, which is less relevant to isolating traffic between internal devices or servers. C. Core/distribution refers to the layers of a network where traffic flows are aggregated and managed. While important for routing traffic, it doesn't focus on isolating device/server traffic. D. North-south refers to traffic that flows between internal networks and external entities (e.g., the internet), which is less relevant to isolating internal traffic.
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interestingtimes 👍 3 Answered AIt's east west because it's the internal network. North south is only when it deals with external networks and servers.
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723b817 👍 3 Answered DI believe it's D because servers usually exist one level up from users.
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interestingtimes 👍 3 Answered AIf it's internal it's east west guys.
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ronnieash88 👍 1 Answered AI’d have. To say East-West it is speaking of data of any sort or in coming or outbound traffic. Yet it refers to an internal firewall where the goal can be to thwart or mitigate lateral attacks if access is gained on the network.
Show 2 more comments
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jcre 👍 1Server to client communication is considered North-South traffic
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Dadadagreat 👍 1D north south
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