ISC Networking · Updated November 2026
Router, Switch, Firewall, DMZ: What Does Each One Do?
Think about where network traffic is going and what control each component performs.
Switch
Connects devices within a network and directs traffic among them using applicable network information.
Router
Connects different networks and routes traffic between them.
Firewall
Enforces traffic rules between network zones based on configured security policies.
DMZ
A demilitarized zone separates externally accessible systems from the more trusted internal network.
The takeaway
Switch connects devices. Router connects networks. Firewall filters traffic. DMZ isolates exposed systems.
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FAQ
Is a firewall the same as a router?
No.
Why use a DMZ?
To isolate externally accessible systems from trusted internal systems.
Does a switch primarily connect separate WANs?
Its typical role is device connectivity within network segments.