There are three basic settings. Here's what each one does.
This turns off your firewall completely. All Internet traffic will be able to reach your network and devices. We only recommend this one if you have to turn it off to test a connection problem.
On this setting your firewall will give you good protection. It'll stop most malicious traffic while still letting more normal Internet traffic through. You'll need to use this if you're using VPN software because it won't work if your firewall's set to High.
If Broadband Firewall has been set on LOW, this is to protect your router from inbound traffic on the following Internet PORTS:
53, 111, 135, 137, 138, 139, 445, 515, 1080, 1433, 3128, 3306, 6000
These ports are generally not used by home or small-business users and your connection is made safer by having them blocked before they reach you.
This setting blocks all unauthorised incoming traffic, so no external source will be able to connect to your network or your devices. Software updates and administrative traffic for Plusnet-provided routers will still be allowed.
It will stop some things working, such as certain apps, VPN software or active FTP sessions. So if you need to use one of those, switch your firewall back to Low.