Lock down a Mac

Turn off the sharing switches you do not use, and keep your Mac updated.

Menu names change a little between versions of macOS. These steps match recent versions. On older Macs, the same switches are in System Preferences under Sharing.

1. Turn off sharing you do not use

Click the Apple menu, then System Settings.
Click General, then Sharing.
You may need to scroll down to find Sharing. Switch off what you do not use: File Sharing, Screen Sharing, Remote Login, Remote Management and Remote Application Scripting. Printer Sharing, Media Sharing and Internet Sharing can go too, if you do not use them.

Remote Login lets someone log in to your Mac from another computer. Screen Sharing and Remote Management let someone view or control your screen.

2. Turn on the firewall

Open the Apple menu, then System Settings.
Click Network in the sidebar, then click Firewall. You may need to scroll down.
Switch the firewall on.

Services that are switched on in the Sharing settings can still get through the firewall, so turning off the ones you do not use (step 1) matters too.

3. Keep your Mac updated

Open System Settings, then General, then Software Update.
Click the small i next to Automatic Updates and switch on the updates you want.
If you use a laptop, keep it plugged in so updates can download.

4. Run the check again

Go back to the free check to see if the warning is gone.

Not comfortable doing this? That is okay.

You do not have to do this alone. You can ask a family member, call your internet company, or take your router to a local computer repair shop. Take your time and ask for help instead of guessing.

Want a professional to look at it? Frequency 42 is the company that makes Network Check, and it offers IT help. You can email support@frequency42.com and ask whether they can help with this.

Then check again

Run the free check again after you make a change.

Run the free check