---
name: "mason"
section: "1"
platform: "linux"
package: "mason"
version: "1.0.0-13"
release: "Debian 12 (Bookworm)"
platforms: ["linux"]
url: "https://new.carta.tech/mason"
---

# mason(1)

interactively create a firewall

## NAME

mason - interactively create a firewall

## SYNOPSIS

**mason** *\< logfile \> rulefile*\

## DESCRIPTION

This manual page briefly documents the **mason** command.

**mason** interactively generates a set of firewall rules for a Linux-based firewall.  This is done by turning on full IP logging, watching the logs for connections, and generating rules describing the connections seen. **mason** is familiar with most of the quirks of various connection types (such as ftp and IRC), and can output rules for 2.0.x ipfwadm, 2.2.x ipchains, and Cisco packet filters.

**mason** operates by reading in log file information from standard input and writing firewall rules to standard output.  This allows **mason** to work offline or on a separate system.  Real-time firewall generation can be achieved with a command like [tail(1)](/tail/1.md).

Most users will want to run mason with a user-friendly interface such as [mason-gui-text(1)](/mason-gui-text/1.md).

## ENVIRONMENT

**mason** is configured using the following environment variables.

- **ECHOCOMMAND**

  Sets the type of firewall rules that **mason** should output to standard out.  Allowed values include "ipfwadm" and "ipchains".  By default, **mason** outputs whatever kind of rules are supported by the currently running Linux kernel.

- **DOCOMMAND**

  Sets the type of firewall rules that **mason** should run immediately when a rule is generated.  Allowed values include "ipfwadm" and "ipchains".  By default, **mason** outputs whatever kind of rules are supported by the currently running Linux kernel.

- **HEARTBEAT**

  If set to "yes", **mason** will output a "+" or "-" to standard error whenever a rule generated by **mason** has been triggered.

- **DYNIP**

  Set this to the list of interfaces that have dynamically assigned addresses, separated by spaces.

## SEE ALSO

**[mason-gui-text(1)](/mason-gui-text/1.md)**

## AUTHOR

This manual page was written by Jeff Licquia \<jeff@luci.org\>, for the Debian GNU/Linux system (but may be used by others).