What is a Firewall and Why do You Need One?
For over 25 years now, firewalls have served as the front line of defence against unknown or untrusted external networks. They work by monitoring inbound and outbound network traffic and using a set of rules to not only identify, but also block threats.
Firewalls can be software, hardware, or even a combination of the two. They are also used in both personal and business settings, as they are generally regarded as an essential part of network security.
What firewalls do
Firewalls act like a barrier or filter for a network. They monitor traffic and block any unwanted or unrecognized traffic by validating traffic according to a set of rules that have been predetermined.
Firewalls can:
- help prevent against spam
- help prevent against malicious actors
- report on activity in a network
- report on threats to a network
- hide and protect internal network addresses and other sensitive information
- block unsolicited incoming network traffic
How firewalls work
Firewalls work by creating a border between the network they are guarding and external networks. They are inserted across a network connection and act like an officer at a real-life border by inspecting every ‘packet’ that enters and leaves the network.
A packet is a chunk of data that has been formatted specifically for transfer via the internet. Packets are made up of data as well as information on the data, like its origin. Firewalls use the information in packets to check if the packet follows the rules that have been set. If the packet does not follow the rules, it cannot enter the network.
The set of predetermined rules that helps firewalls decide what packets are malicious and cannot enter the network are based on information packet data, like:
- Source (where the data comes from)
- destination (where the data is supposed to go)
- content (what the packet contains)
There are different types of firewalls that read packets at different levels of a network. Packets are reformatted multiple times on their route through a network so that the protocol will know where to send it.
Types of firewalls
There are multiple types of firewalls, but these are the three most common:
- Packet filtering – packets trying to enter the network are put through various filters which remove packets that match predetermined threats. “Safe” packets can continue to their destination.
- Proxy service – Less like a security guard and more like a middle-man, proxy service firewalls create a sort of duplicate of the protected network. They do this to prevent a direct connection between the protected network and incoming packets.
This type of firewall is very secure, but slower than the other two types and don’t work with all applications.
- Stateful inspection – this type of firewall is like the chief officer at a border. Stateful inspections check several elements in every incoming data packet and cross examine them according to pre-existing trusted information. Some elements are ports, applications, destination IP addresses, and sources.
Why small businesses need firewalls
Beyond the main reasons why small businesses need firewalls, like protecting themselves from malicious threats, there are a few other reasons too:
- Firewalls can be configured to block access to certain websites – users on a network, say the small business’ employees, can be stopped from accessing certain websites like Facebook, TikTok or Instagram to make sure that there is not any slacking on company time.
- Firewalls can meter bandwidth – similarly, it is possible to use firewalls to put a cap on the amount of network bandwidth allowed for any non-business activities like music, images, videos, and more. This reserves bandwidth for priority traffic, which is business traffic.
- VPN services – many firewalls can provide connectivity for remote sites via a virtual private network (VPN) which enables remote work and access to internal network resources in a secure manner.
Firewall protection is a part of any good cyber security strategy, especially for small businesses that deal with sensitive customer information and may have employees working remotely. Contact us today, we offer managed IT services, cloud services, cyber security, data security, IT helpdesk, custom software, and more! Get in touch with us today for more info on IT solutions.
