macfw 0.1.3

A small pf-based firewall manager for macOS with a ufw-like CLI

macfw

macfw is a small pf-based firewall manager for macOS with a ufw-like CLI.

A ufw-like firewall CLI for macOS.

Built for Macs that behave more like servers, especially in IPv6-exposed environments.

Why • Quick Start • Installation • Common Commands • Rule Model • Default Policy

It is designed for one common use case:

• keep loopback, LAN, and trusted private ranges reachable
• keep outbound traffic open
• deny public inbound traffic by default
• allow or deny explicit inbound exceptions with a short CLI

In practice, you can think of it as:

• a macOS firewall CLI
• a ufw-like firewall tool for macOS
• a simple way to manage public inbound exposure on a Mac that behaves more like a server than a personal laptop

Why this exists

macfw exists to solve a gap that becomes obvious in IPv6-heavy home lab and self-hosting environments.

Many people now run a Mac, especially a Mac mini, as a small always-on server for tools, automation, coding agents, model runtimes, remote access, or NAS-like tasks. A particularly important example is people running OpenClaw on a Mac mini as a long-lived agent host. In that role, the machine is no longer just a daily personal computer. It starts behaving more like a Linux VPS, a home server, or a small self-hosted node that needs controlled inbound access.

On IPv4 networks, NAT often provides an extra layer between the machine and the public internet. On IPv6 networks, that assumption is much weaker. A Mac can end up directly reachable from the public internet, which means every listening service deserves deliberate review.

macOS does include firewall features, but the built-in experience is mostly app-oriented and GUI-oriented. It is not a close equivalent to the Linux ufw workflow many server users expect when they want to answer simple questions such as:

• which inbound ports are currently meant to be reachable from the public internet
• how do I allow only one port
• how do I allow only IPv4 or only IPv6
• how do I remove or deny a rule from the command line

macfw is built for that gap. It gives a Mac server or Mac mini a small command-line firewall workflow that feels much closer to ufw, while still using macOS pf underneath.

Who this is for

macfw is especially meant for people who:

• run OpenClaw or similar always-on agent workloads on a Mac mini
• run a Mac mini or another macOS machine as an always-on server
• use IPv6 and want tighter control over public inbound exposure
• prefer terminal-based rule management over GUI-only firewall tools
• want a simpler mental model similar to ufw rather than raw pf.conf editing

Status

macfw is currently an early 0.1.x release. The rule model is usable, but the project should still be treated as a careful admin tool rather than a polished end-user app.

Requirements

• macOS
• Python 3.9+
• pfctl
• sudo access for commands that touch /etc or load pf

This project is for macOS only. It is not intended for Linux, BSD routers, or Windows.

Install

Recommended: install from PyPI with pipx

pipx is the best default for a CLI tool because it keeps the application isolated while still exposing the macfw command on your shell PATH.

python3 -m pip install --user pipx
pipx install macfw
macfw --version

Upgrade later:

pipx upgrade macfw

Alternative: install from PyPI with pip

If you prefer a plain Python environment instead of pipx:

python3 -m pip install macfw
macfw --version

Development: install from a local clone

git clone https://github.com/tudoujunha/macfw.git
cd macfw
python3 -m pip install .

Development: install directly from GitHub

python3 -m pip install git+https://github.com/tudoujunha/macfw.git

Development: isolated CLI install from GitHub with pipx

pipx install git+https://github.com/tudoujunha/macfw.git

Before you start

You need to know which network interface receives the inbound traffic you want to protect.

Common examples:

• Wi-Fi: often en0 or en1
• Ethernet or USB adapters: often another enX

Useful commands:

ifconfig
networksetup -listallhardwareports
route -n get default

If you are not sure, check which interface currently has your LAN or public IP address, then use that interface for macfw install --interface ....

Quick start

Install the managed anchor and choose the network interface to protect:

sudo macfw install --interface en1

Check the current state before enabling anything:

macfw status
sudo macfw status

If you need SSH from the public internet, allow it before enabling the firewall:

sudo macfw allow 22/tcp

Enable the firewall:

sudo macfw enable

Show current state again:

macfw status
sudo macfw status

Disable or uninstall later:

sudo macfw disable
sudo macfw uninstall

First-time setup checklist

Recommended order:

1. Install the anchor with the correct interface
2. Review the default policy with macfw status
3. Add any public inbound exceptions you need, such as 22/tcp
4. Enable the firewall
5. Open a new test connection from the network you care about
6. Only then close the old session

This matters because enabling pf can interrupt an already-established SSH connection.

Default policy

• allow loopback traffic
• allow inbound traffic from the active interface network
• allow inbound traffic from private RFC1918 IPv4 ranges
• allow inbound traffic from 100.64.0.0/10
• allow inbound traffic from fe80::/10 and fd00::/8
• allow outbound traffic
• deny public inbound traffic unless a rule explicitly allows it

Rule model

Each rule answers four questions:

• from <source>: who may connect
• port <port|all>: which local port is reachable
• proto <proto>: which protocol applies
• family <both|ipv4|ipv6>: which IP family applies

Supported protocols today:

• tcp
• udp
• icmp
• icmp6
• any

Common commands

macfw allow 22/tcp
macfw allow 53/udp
macfw allow 22/tcp ipv6
macfw allow 22/tcp from any ipv4
macfw allow 22/tcp from 1.2.3.4
macfw allow 22/tcp from 2001:db8::1
macfw allow proto icmp ipv4
macfw allow from 192.168.0.0/16

macfw deny 22/tcp ipv6
macfw deny 22/tcp from 2001:db8::1

macfw delete 22/tcp
macfw delete 22/tcp ipv6
macfw delete deny 22/tcp ipv6
macfw delete from 192.168.0.0/16

Common scenarios

Allow public SSH on IPv6 only:

sudo macfw allow 22/tcp ipv6

Allow public DNS on UDP:

sudo macfw allow 53/udp

Allow SSH only from one specific address:

sudo macfw allow 22/tcp from 203.0.113.10
sudo macfw allow 22/tcp from 2001:db8::10

Explicitly block a public IPv6 SSH rule:

sudo macfw deny 22/tcp ipv6

Remove a single matching rule without caring whether it is allow or deny:

sudo macfw delete 22/tcp

Delete matching behavior

delete uses two matching modes:

• if you specify allow or deny, deletion is constrained to that action
• if you do not specify an action, macfw looks for all matching rules

That means:

• if exactly one rule matches, delete removes it even if it is a deny
• if multiple rules match, delete stops and asks you to disambiguate with allow, deny, ipv4, ipv6, or a more specific source

Family matching works like this:

• omit ipv4 or ipv6: broader family match
• specify ipv4 or ipv6: exact family match

Examples:

# removes 22/tcp, 22/tcp ipv4, or 22/tcp ipv6 if there is only one match
sudo macfw delete 22/tcp

# removes only an IPv6 rule
sudo macfw delete 22/tcp ipv6

# removes only a deny rule
sudo macfw delete deny 22/tcp ipv6

Status output

macfw status shows:

• whether macfw is enabled
• whether live pf is enabled
• which interface is managed
• your user-defined rules first
• built-in trusted defaults
• the final default deny

If pf shows as unknown, run:

sudo macfw status

What install, enable, reload, and disable do

• install: creates the macfw anchor, injects the anchor hook into /etc/pf.conf, and writes the local config files
• enable: writes the active anchor rules, validates the pf config, and enables pf if needed
• reload: rewrites and reloads the anchor using the current config
• disable: keeps the config on disk but disables the active macfw policy
• uninstall: removes the anchor, restores the original /etc/pf.conf backup when available, and removes the local config files

Safety notes

Be careful when enabling or reloading rules over SSH.

• enabling pf can drop an already-established SSH session
• a newly opened LAN SSH session should still match the LAN allow rules
• a public SSH session will be dropped unless you explicitly allow it first

If you rely on public SSH access, add the rule before enabling:

sudo macfw allow 22/tcp
sudo macfw enable

If you rely on LAN SSH only, the default trusted LAN rules should permit a newly opened LAN session after the firewall is enabled. An already-established session can still drop when pf first becomes active.

How it works

macfw manages:

• a dedicated anchor at /etc/pf.anchors/macfw
• a hook in /etc/pf.conf
• a user config at ~/.config/macfw/config.json
• a small state file at ~/.config/macfw/state.json

install backs up the current /etc/pf.conf before modifying it. uninstall restores the backup when available.

Limitations

• there is no Homebrew formula yet
• there is no PyPI release yet
• interface detection is not automatic yet
• this tool is focused on inbound filtering on macOS pf
• this tool assumes you are comfortable using sudo and reading firewall state before enabling changes

Development

Run the test suite:

python3 -m unittest discover -s tests -v

Run directly from the repository checkout:

PYTHONPATH=. python3 -m macfw --help

For maintainer release steps, see:

• docs/publishing.md

License

MIT