How to Enable and Configure Windows Firewall Correctly
What it does, how to confirm all three network profiles are on, how to allow one blocked program without opening the whole system up, and why a third-party antivirus firewall usually replaces it rather than stacking on top.
Windows already includes its own firewall, enabled by default, with nothing extra to install or pay for. This article explains exactly what it does, how to check it is properly configured, and what to do if it is blocking something you actually want to use.
Plain-language explanation
A firewall is a filter between your computer and the internet: it decides which connections to let through and which to block, so that unauthorised programs cannot communicate with your machine from outside without your knowledge.
Check that it is enabled
Search for "Windows Security" → "Firewall & network protection". You will see three profiles: domain network (corporate environments), private network (your home) and public network (cafés, airports). Each is enabled separately, and all should be set to "On" unless you have a specific reason otherwise.
Private vs public network: mark your home network as "private" — it lets your own devices see each other (useful for sharing files, for example). On a public network, Windows is much more restrictive by default — and rightly so, since you do not know or trust the other devices connected there.
If the firewall blocks a program you do want to use
There is no need to disable the entire firewall for a single program. In "Firewall & network protection" → "Allow an app through firewall" → find the program in the list (or "Change settings" → "Allow another app" if it does not appear) → check the private and/or public network boxes as appropriate.
Tip: Windows automatically creates the necessary exceptions for most well-known programs when you install them — you will only need to touch this manually for less common programs, like some networked games or specific tools.
Warning: disabling the firewall entirely (instead of allowing just the specific program that needs it) leaves the whole machine more exposed, not only that application. It is an almost always disproportionate solution.
If you have an antivirus with its own firewall
Some third-party security programs include their own firewall. Having two firewalls active at once can cause conflicts (double blocking, network slowness) — the usual behaviour is that a third-party antivirus automatically disables Windows' when it is installed, but it is worth checking if you notice odd network behaviour after installing a new one.
Note: this article covers the basic configuration, enough for normal home use. Windows also lets you create very specific rules by port and protocol from "Advanced settings" — these are meant for particular cases (your own servers, work environments) and are not needed for everyday use.
Frequently asked questions
Do I need to install a third-party firewall in addition to Windows'?
No, for normal home use. Windows' built-in firewall is enough on its own — installing an additional one can even cause conflicts if both are active at once.
Does disabling the firewall improve internet speed?
Not noticeably, and in exchange it exposes the machine to more risk. If you suspect the firewall is affecting a specific program's performance, it is better to create an exception for that program than to disable it entirely.
How do I know if the firewall is blocking a specific program?
If a program that needs internet (for example, for local network multiplayer) does not connect well, check 'Allow an app through firewall' and confirm it has the private and/or public network boxes checked as needed.