Filtering traffic.
WHAT A FIREWALL DOES
Controls what traffic is allowed in and out.
WHERE THEY EXIST
On your router On individual devices In front of websites and services
WHAT TO ENABLE
The firewall on every device.
Most operating systems include one. Leave it on.
WHAT TO CONFIGURE ON A ROUTER
Block incoming connections you did not intend to allow.
WHAT TO BE CAREFUL WITH
Port forwarding, which exposes an internal device to the internet.
Only where genuinely necessary, and secured.
WHAT A WEBSITE FIREWALL ADDS
Filtering malicious requests before they reach the application.
WHAT NONE OF THEM DO
Protect against a person being deceived Substitute for updates
WHAT TO AVOID
Disabling protection to make something work.
Establish why it is blocked instead.
WHAT TO CHECK
What is exposed externally.
WHAT TO DOCUMENT
Any rule you add, and why.
Undocumented rules accumulate and nobody dares remove them.
