What a business firewall does, and why the one from your internet provider is not enough

Every office has a box where the internet comes in. In many small businesses, that box is whatever the internet provider supplied, doing the job of modem, router, Wi-Fi and firewall all at once. It works, in the sense that the internet is there. This article explains what a business firewall does differently and why we recommend one for most offices.

What a firewall is

A firewall sits between your office network and the internet and decides what traffic is allowed through in each direction. Anything from the internet that nobody inside asked for is blocked, which stops most attempts to reach your computers directly. A good firewall also looks at what goes out, so a computer that has been infected cannot quietly send data to an attacker.

What the provider's box does not do

The equipment from an internet provider is built to be cheap and to work out of the box. It usually has basic blocking of unsolicited traffic and not much else: no inspection of the content of traffic, no blocking of known malicious websites, little or no logging, infrequent security updates, and often a default admin password that has never been changed. It typically cannot separate staff, guest and device traffic, and it cannot give you a secure way to reach the office from outside.

What a business firewall adds

Blocking of known malicious and phishing websites for every device on the network, including phones and devices we do not manage. Inspection of traffic for malware and attacks. Separate networks for staff, guests, payment terminals and smart devices, so a problem in one cannot reach the others; see Guest Wi-Fi. Secure remote access, a VPN, so staff can reach office systems safely from home. Logs that let us see what happened when something goes wrong. Regular security updates, applied by us. And it is managed: we can see its health in our monitoring and change settings remotely.

What it does not replace

A firewall protects the office network. It does not protect a laptop in a coffee shop, an email account with a weak password or a phone with work mail on it. That is why Microsoft Defender, multi-factor authentication and updates still matter; the firewall is one layer among several.

Cost and setup

A firewall suitable for a small office is a modest one-time purchase plus, for some models, an annual subscription for the security features. We take no margin on the hardware, and installing it is quoted as a small project, usually done outside working hours so nobody notices the change. If you are unsure what sits between your office and the internet today, our free IT assessment will tell you.