Open Network, choose the Firewall tab, click Set Up Firewall… and then Turn On in the guide. macOS then asks you to approve Aegisrook twice: once in System Settings, and once in a window asking to filter network content, where you click Allow. It takes about a minute.
Before you start
Aegisrook must be in your Applications folder. If it isn’t, the firewall can’t be installed and Aegisrook tells you so. Move it there and open it again.
Turn it on
- In Aegisrook, open Network, choose the Firewall tab and click Set Up Firewall…. (The setup list has the same button.) A guide opens and updates as you finish each step. Click Turn On in it.
- macOS asks you to approve Aegisrook. Click Open Login Items & Extensions in the guide, or open System Settings › General › Login Items & Extensions. Scroll to the extensions, click the Info button (ⓘ) next to Network Extensions and turn on Aegisrook. If you don’t see Network Extensions, switch the list from By App to By Category. Enter your password if asked.
- A window appears: “Aegisrook” Would Like to Filter Network Content. Click Allow.
When the guide shows that the firewall is on, you’re done. From now on, Aegisrook asks you the first time each new app tries to connect.
What happens next
- Apps you already have are allowed automatically. Apps in your Applications folder when you turn the firewall on get an Allow rule, so they aren’t asked about.
- The first days bring more questions. New apps and other programs are each asked about once. Allow the ones you use and the questions settle down.
- Your answer sticks. In the question window, Remember is set to Always unless you choose a shorter time. You can change any answer later in the Rules tab, where every rule is listed.
- Apple’s own programs aren’t asked about, except tools that malware often misuses, such as curl and osascript.
Choose how strict it is
In the Firewall tab, under When an Unknown App Connects, choose:
- Ask Me to see a question each time (the default)
- Allow Without Asking for a quiet mode
- Block Without Asking, the strictest
You can set a different choice for On Wi-Fi Without a Password, such as cafés, hotels and airports. Block Without Asking is a good choice there. On This Network sets a choice for the network you’re on now.
Turn it off
Click Turn Off in the Firewall tab. Your rules are kept for next time. To remove the firewall from your Mac completely, see Uninstall Aegisrook.
If the firewall doesn’t turn on, see The firewall won’t turn on.