Change one rule at a time
Test the app after each change so you can identify which connection it needs.
Block internet access for Mac apps
Stop a Mac app from accessing the internet while keeping other apps online. Use LuLu to block outgoing connections and manage app permissions.
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An app may connect in the background even when you are not actively using it. If you want to control one app’s network access, turning off Wi-Fi also disconnects everything else.
LuLu lets you allow or block outgoing connections for individual apps. Follow the steps below to create a rule and change it later. Blocking a connection can also stop that app’s updates, downloads or cloud sync.
Smartin
Choose where to start
Step 1 of 4
Install LuLu
Download LuLu from Objective-See. Open the disk image, move LuLu to Applications, then launch it.
Download LuLu ↗
Step 2 of 4
Choose your settings
Review the automatic allow settings. If you want prompts for installed apps, check whether they already have permission or an existing allow rule.
Step 3 of 4
Block the app
Open the app and trigger an online action. When an alert appears, check the process name and choose Block.
Step 4 of 4
Manage your rules
Open Rules from LuLu’s menu-bar icon. Find your app and edit or remove its block rule whenever you want to restore access.
Block connections initiated by other devices. This does not stop the app accessing the internet.
Open Firewall settings
Open Apple menu → System Settings → Network → Firewall.
Turn on Firewall
Turn on Firewall, then open Options to manage incoming connections for individual apps.
Add the app and block incoming connections
Click the add (+) button, select the app and add it to the list. Use the menu beside the app to choose Block incoming connections, then click OK.
Review or change the rule
Return to Firewall → Options whenever you want to change the app’s setting. Choose Allow incoming connections to permit them again.
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Is LuLu free?
Yes. LuLu is a free, open-source firewall from Objective-See.
Can I unblock an app later?
Yes. Open LuLu’s Rules window, find the app, then edit or remove its block rule.
Will a blocked app still work offline?
Local features may still work. Features that need the internet, such as cloud sync and downloads, will not work while their connections are blocked.
Why am I not seeing a connection alert?
The app may already have an allow rule or be covered by automatic allow settings. Check its rules and LuLu’s settings.
Does blocking one app disconnect my Mac?
No. A rule for one app applies to that app’s connections. Other apps can continue using the internet.
Check background helpers
An app may use a separate helper process. Check the process named in the alert before creating a rule.
Keep a note of your changes
Record which rules you changed so you can restore access later.
Tools
- LuLu for Mac
Downloads
LuLu for MacOfficial download from Objective-SeeReferences
LuLu source and issuesProject repository and issue trackerIncoming connections
macOS FirewallApple’s setup instructions · Built into macOS
