What are the differences between a router, a firewall, and a switch?

In nearly every network, three fundamental devices are commonly employed: a network switch, a network router, and a network firewall. While these devices can be combined into a single unit for smaller networks like home networks, this is not typically the case for larger networks. It is important to note that none of the three devices can be overlooked or disregarded in any network configuration.

In this post, we will learn how a router, a firewall, and a switch are different.

A Network Switch

Within a local area network (LAN), the network switch operates in a manner akin to the bridges found in cities, connecting various network devices like switches, routers, firewalls, and Wireless access points (WAPs) connect client devices such as computers, servers, Internet Protocol (IP) cameras, and IP printers. Acting as a centralized hub, a WAP facilitates connections between the various devices on the network.

How does a network switch work?

A network switch operates by efficiently transferring data frames. It uses a stored table that records which Media Access Control (MAC) addresses it has observed on specific switch ports. MAC addresses are unique identifiers embedded in the hardware of network interface controllers (NICs) found in network cards, switches, and routers. The switch learns the source and destination MAC addresses through the data frames it processes and maintains this information in its table.

By referencing this table, the switch determines the appropriate port for incoming frames. If it encounters a destination MAC address not in its table, the switch broadcasts the frame to all switch ports, a process known as flooding. When it receives a response, the switch adds the corresponding MAC address to its table, eliminating the need for future flooding for that address.

A Network Router

Routers also referred to as Gateways, are physical devices utilized to direct packets between diverse networks and establish connections between your network and the Internet. In reality, the Internet itself consists of a vast network comprising hundreds of thousands of routers.

How does a network firewall router work?

A router examines the source and destination IP addresses of every packet, consults its IP routing table to find the packet’s intended destination, and forwards the packet to another router or switch. This process continues until the packet reaches the destination IP address and receives a response.

When multiple routes are available to the destination, routers can intelligently select the most efficient path. If the routing table does not list a specific destination, the router sends the packet to the default router (if configured). If no valid destination exists for the packet, the router discards it.

A Network Firewall router

Firewalls serve as protective barriers in computer networks. Specifically, a network firewall creates a barrier between an intranet or local area network (LAN) and the Internet. Its primary purpose is to safeguard the internal LAN from external attacks and prevent unauthorized leakage of sensitive data.

Unlike routers, which simply forward traffic between networks, firewalls actively monitor traffic flow and block unauthorized network traffic from exiting.

How does a network firewall work?

A prevalent form of hardware firewall allows users to establish custom blocking rules based on factors like IP address, Transmission Control Protocol (TCP), or User Datagram Protocol (UDP) port numbers. This configuration lets the firewall block unwanted ports and IP addresses from accessing the network.

In addition, software applications and services can also function as firewalls. These firewalls operate similarly to proxy servers, acting as intermediaries between two networks. In this setup, the internal network communicates only with the firewall, not directly with the external network. Combining hardware and software firewalls generally provides a more secure and efficient approach.

Conclusion

Switches facilitate internal communication within your local area network (LAN), routers establish connectivity to the Internet, and firewalls ensure network security. You cannot overlook any of these components in a network setup.

In smaller networks, you often find a single integrated device that combines the functions of switches, routers, and firewalls. However, larger networks, such as enterprise networks, data centers, and Internet service providers, typically include all three components. This setup helps them manage multiple, complex, and highly secure communications effectively.