LuLu

Name: LuLu
Brand: LuLu

Free, open-source firewall for macOS that blocks unauthorized outgoing connections.

softwareFirewalls FirewallmacOS SecurityOpen Source

What is LuLu?

LuLu is a free and open-source firewall for macOS built by Objective-See, designed to monitor and control outgoing network connections rather than inbound traffic. It alerts users whenever an unknown or unrecognized process attempts to connect out to the network, helping catch malware trying to exfiltrate data or reach command-and-control servers.

SpecificationsAI-estimated

deploymentDesktop App

open source✅ Yes

Key Features of LuLu

Alerts in real time whenever an unrecognized application attempts an outgoing network connection.

Verifies code signing to help distinguish trusted processes from suspicious or unsigned ones.

Integrates with VirusTotal to check flagged processes against known threat databases.

Supports customizable allow and block rules with granular control over destination and duration.

Offers Passive, Block, and Normal operational modes depending on how strict the user wants enforcement.

Includes a built-in network monitor called Netiquette for viewing current network activity.

Supports rule profiles and import/export for managing configurations across setups.

Is fully open source, with its code and release history published on GitHub.

Use Cases for LuLu

Malware Exfiltration Detection

Catch malicious software attempting to phone home or exfiltrate data over outbound connections.

Privacy-Conscious Network Control

Block unwanted applications from silently sending telemetry or data off the device.

App Behavior Auditing

Use the Netiquette monitor to observe which applications are making network connections and where.

Security Research

Inspect and control network behavior of unfamiliar or newly installed applications on a Mac.

Pros & Cons of LuLu

Pros

Completely free and open source, including the source code on GitHub
Effective at catching malware attempting outbound data exfiltration
Built by Objective-See, a developer with a strong reputation in Mac security tooling
Granular per-app, per-destination rule control

Cons

macOS only, no Windows or Linux version
Frequent connection alerts can be noisy until rules are tuned
Requires some technical familiarity with network processes to configure effectively

Frequently Asked Questions

Is LuLu really free?

Yes, LuLu is completely free and open source, developed by Objective-See with no paid tier.

What does LuLu protect against?

It monitors and alerts on outgoing network connections, helping catch malware attempting to exfiltrate data or contact command-and-control servers.

What macOS versions does LuLu support?

LuLu supports macOS 10.15 and later.

Is LuLu's source code available?

Yes, LuLu is open source with its code and releases published on GitHub at github.com/objective-see/LuLu.

Pricing Overview

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Free

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