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), while simultaneously linking client devices such as computers, servers, Internet Protocol (IP) cameras, and IP printers. Acting as a centralized hub, it facilitates connections between the different devices present on the network.
How does a network switch work?
A network switch operates by efficiently transferring data frames, utilizing a stored table that records which Media Access Control (MAC) addresses have been 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 acquires knowledge of 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 to direct incoming frames. If it encounters a destination MAC address not present in its table, the switch broadcasts the frame to all switch ports, a process is known as flooding. Upon receiving a response, the switch adds the corresponding MAC address to its table, eliminating the need for future flooding concerning 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 router work?
A router examines the source and destination IP addresses of every packet, consults its IP routing table to determine the packet’s intended destination, and forwards the packet to another router or switch accordingly. This process repeats until the packet reaches the destination IP address and receives a response.
In cases where multiple routes are available to reach the destination IP address, routers can intelligently select the most efficient path. If the routing table does not list a specific destination for the packet, it is sent to the default router (if configured). However, if there is no valid destination defined for the packet, it will be discarded.
A Network Firewall
Firewalls function as protective barriers in the realm of computer networks. Specifically, a network firewall establishes a barrier between an intranet and local area network (LAN) and the Internet. Typically, its primary purpose is to safeguard the internal LAN from external attacks and prevent the unauthorized leakage of sensitive data. Unlike routers that lack firewall capabilities and simply forward traffic between separate networks, firewalls actively monitor the traffic flow and prohibit the egress of unauthorized network traffic.
How does a network firewall work?
A prevalent form of hardware firewall enables users to establish custom blocking rules based on factors like IP address, Transmission Control Protocol (TCP), or User Datagram Protocol (UDP) port numbers. This allows the firewall to prohibit unwanted ports and IP addresses from accessing the network.
On the other hand, there are also software applications and services that function as firewalls. These firewalls operate similarly to proxy servers, acting as intermediaries between two networks. In this setup, the internal network does not directly communicate with the external network. Combining these two types of firewalls is generally considered a more secure and efficient approach.
Switches facilitate internal communication within your local area network (LAN), routers establish connectivity to the Internet, and firewalls ensure the security of your network. Each of these components is essential and cannot be overlooked in a network setup.
In smaller networks, it is common to find a single integrated device that combines the functionalities of switches, routers, and firewalls. However, in larger networks such as enterprise networks, data centers, and Internet service providers, all three components are typically present to handle multiple, intricate, and highly secure communications.
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