How to Turn On the Firewall on Your Windows PC or Mac

Your computer talks to the internet constantly — checking for new email, downloading updates, syncing photos. A firewall is the part of your computer that decides which of those conversations are allowed and which ones look unwanted. Think of it as a quiet gatekeeper that runs in the background, checking traffic before it reaches you.

Both Windows and Mac computers come with a firewall built in, and on most computers it's already turned on. But it's worth checking, especially if you've had a computer for a while or someone else set it up for you. This guide shows you how to find it and turn it on if it isn't already.

You won't need to install anything. Everything here uses a feature that's already part of your computer.

What a firewall actually does

A firewall watches the connections coming into your computer from the internet and blocks the ones it doesn't recognize as safe. It doesn't scan your files for viruses, and it doesn't stop you from visiting a website — that's a different job, handled by antivirus software and your web browser. A firewall's job is narrower: it keeps unwanted incoming connections from reaching your computer in the first place.

Turning it on doesn't slow your computer down or change how your normal programs work. You'll keep browsing, emailing, and video-calling exactly as before.

Windows calls its version Microsoft Defender Firewall, and Mac's version is simply called Firewall. Neither one is a separate program you need to buy or download — both are already built into the settings you use every day, just not always turned on by default.

How to check the firewall on a Windows PC

1. Press the Windows key and the I key at the same time to open Settings. You can also click the Start menu and look for the gear-shaped Settings icon.
2. Click Privacy & security in the left-hand list.
3. Click Windows Security, then Firewall & network protection.
4. You'll see a list of networks — usually Domain network, Private network, and Public network. Click the one you're currently connected to (most home Wi-Fi is "Private network").
5. Look for a switch labeled Microsoft Defender Firewall. If it already shows On, you're done. If it shows Off, click it to turn it on.

You need to be signed in as the computer's administrator to change this setting. If you don't manage the computer yourself — for example, a family member or workplace set it up — you may see a message that the setting is controlled elsewhere, and that's expected.

How to check the firewall on a Mac

1. Click the Apple menu in the top-left corner of your screen, then choose System Settings.
2. Click Network in the left-hand list.
3. Scroll down and click Firewall. (On some older versions of macOS, this is under Security & Privacy instead.)
4. If the switch next to Firewall is off, click it to turn it on.

Once it's on, Mac also offers an Options button where you can turn on "stealth mode," which makes your computer harder for unwanted connections to even find. That's optional — the firewall does its main job either way.

What to do if you're stuck

If you don't see the settings described above, or a button is grayed out, your computer may be managed by a family member, employer, or senior community's IT department, and changing it isn't up to you. That's not a mistake on your part — it simply means someone else has set the rule for this computer. This is common on a computer provided by a workplace, or on a shared computer in a senior community's computer lab, where IT staff sets these rules the same way for everyone who uses it.

If anything here feels confusing, or you'd rather not do it alone, in-home and remote computer help is available, and we're glad to check it with you.

A firewall is one piece of the picture

A firewall blocks unwanted connections, but it won't warn you about a scam pop-up, a phishing email, or a dangerous website — those need a different kind of protection, with someone paying attention on your behalf.

If you want quiet protection on your Windows or Mac computer — with a real Porchswing person to call — learn about PorchswingProtect. Or call us at (916) 521-0065 and we'll help you set it up.

Common questions

Will turning on the firewall break anything I already use?

No. Your email, web browser, video calls, and other everyday programs will keep working the same way. The firewall only affects unwanted incoming connections, not the programs you already trust.

Do I need the firewall if I already have antivirus software?

Yes — they do different jobs. Antivirus software looks for harmful software already on your computer. The firewall blocks unwanted connections from reaching your computer in the first place. Both running together is normal and recommended.

Is my computer unsafe if the firewall was off?

Not necessarily, especially if you're on a private home network and keep your software updated. But turning it on is a quick, free way to add a layer of protection, so it's worth doing today.