LuLu is the best free outbound firewall for Mac, and you probably shouldn't replace it if blocking is what you need. It alerts on new connections and lets you allow or block them. What it doesn't aim to do is show your traffic: bytes per app, every connection's destination on a map, listening ports, or the domain names behind IP addresses. That's LightAtom's job, and the two work well side by side.
Who this is for
- You use LuLu and want to know what the apps you allowed are actually doing.
- You find alert-driven firewalls tiring and would rather browse a live view.
- You need to explain a Mac's traffic to someone else, with a map and per-app totals.
Comparison
| LightAtom | LuLu | |
|---|---|---|
| Price | Not announced yet | Free |
| Platforms | macOS | macOS |
| Blocks connections | No | Yes |
| Per-app bytes / live rate | Yes | Not listed |
| Map view | Yes | Not listed |
| Open ports view | Yes | Not listed |
| DNS / domain names | Yes | Not listed |
| Open source | Not listed | Yes |
| macOS support | macOS 14 or later | macOS 10.15 or later |
| Last checked | 24 Oct 2026 | 24 Oct 2026 |
When to stay with LuLu
Stay with LuLu if you want a free, open-source firewall that blocks outbound connections, with per-app or per-endpoint rules and block lists. LightAtom doesn't block, so if blocking is the point, LuLu (or Little Snitch) is the right tool.
How to switch
- Keep LuLu installed if you rely on its rules; LightAtom doesn't conflict with it.
- Install LightAtom and let it run while you work normally.
- Compare apps you allowed in LuLu with their actual traffic in the connections view.
Frequently asked questions
Is LuLu really free?
Yes. LuLu is free and open source, made by Objective-See.
Does LuLu show network traffic?
It shows alerts and rules. Objective-See's separate Netiquette tool lists current connections. Neither focuses on bytes per app over time.
What is the difference between LuLu and LightAtom?
LuLu decides which connections are allowed. LightAtom shows every connection, its app, destination, domain and data volume, without blocking.
Which macOS versions does LuLu support?
macOS 10.15 or later, according to Objective-See.