---
name: "firehol"
section: "1"
platform: "linux"
package: "firehol"
version: "3.1.8+ds-1"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/firehol"
---

# firehol(1)

an easy to use but powerful iptables stateful firewall

## NAME

firehol - an easy to use but powerful iptables stateful firewall

## SYNOPSIS

firehol

sudo -E firehol panic \[ *IP* \]

firehol *command* \[ – *conf-arg*... \]

firehol *CONFIGFILE* \[start\|debug\|try\] \[– *conf-arg*... \]

## DESCRIPTION

Running `firehol` invokes [iptables(8)](/iptables/8.md) to manipulate your firewall.

Run without any arguments, `firehol` will present some help on usage.

When given *CONFIGFILE*, `firehol` will use the named file instead of `/etc/firehol/firehol.conf` as its configuration. If no *command* is given, `firehol` assumes `try`.

It is possible to pass arguments for use by the configuration file separating any conf-arg values from the rest of the arguments with `--`. The arguments are accessible in the configuration using standard [bash(1)](/bash/1.md) syntax e.g. $1, $2, etc.

### PANIC

To block all communication, invoke `firehol` with the `panic` command.

FireHOL removes all rules from the running firewall and then DROPs all traffic on all [iptables(8)](/iptables/8.md) tables (mangle, nat, filter) and pre-defined chains (PREROUTING, INPUT, FORWARD, OUTPUT, POSTROUTING).

DROPing is not done by changing the default policy to DROP, but by adding one rule per table/chain to drop all traffic. This allows systems which do not reset all the chains to ACCEPT when starting to function correctly.

When activating panic mode, FireHOL checks for the existence of the SSH\_CLIENT shell environment variable, which is set by [ssh(1)](/ssh/1.md). If it finds this, then panic mode will allow the established SSH connection specified in this variable to operate.

**Note**

In order for FireHOL to see the environment variable you must ensure that it is preserved. For [sudo(8)](/sudo/8.md) use the `-E` and for [su(1)](/su/1.md) omit the `-` (minus sign).

If SSH\_CLIENT is not set, the *IP* after the panic argument allows you to give an IP address for which all established connections between the IP address and the host in panic will be allowed to continue.

## COMMANDS

- start; restart

  Activates the firewall using `/etc/firehol/firehol.conf`.

  Use of the term `restart` is allowed for compatibility with common init implementations.

- try

  Activates the firewall, waiting for the user to type the word `commit`. If this word is not typed within 30 seconds, the previous firewall is restored.

- stop

  Stops a running [iptables(8)](/iptables/8.md) firewall by clearing all of the tables and chains and setting the default policies to ACCEPT. This will allow all traffic to pass unchecked.

- condrestart

  Restarts the FireHOL firewall only if it is already active. This is the generally expected behaviour (but opposite to FireHOL prior to 2.0.0-pre4).

- status

  Shows the running firewall, using `/sbin/iptables -nxvL | less`.

- save

  Start the firewall and then save it using [iptables-save(8)](/iptables-save/8.md) to the location given by FIREHOL\_AUTOSAVE. See [firehol-defaults.conf(5)](/firehol-defaults.conf/5.md) for more information.

  The required kernel modules are saved to an executable shell script `/var/spool/firehol/last_save_modules.sh`, which can be called during boot if a firewall is to be restored.

  **Note**

  External changes may cause a firewall restored after a reboot to not work as intended where starting the firewall with FireHOL will work.

  This is because as part of starting a firewall, FireHOL checks some changeable values. For instance the current kernel configuration is checked (for client port ranges), and RPC servers are queried (to allow correct functioning of the NFS service).

- debug

  Parses the configuration file but instead of activating it, FireHOL shows the generated [iptables(8)](/iptables/8.md) statements.

- explain

  Enters an interactive mode where FireHOL accepts normal configuration commands and presents the generated [iptables(8)](/iptables/8.md) commands for each of them, together with some reasoning for its purpose.

  Additionally, FireHOL automatically generates a configuration script based on the successful commands given.

  Some extra commands are available in `explain` mode.

  - help

    Present some help

  - show

    Present the generated configuration

  - quit

    Exit interactive mode and quit

- helpme; wizard

  Tries to guess the FireHOL configuration needed for the current machine.

  FireHOL will not stop or alter the running firewall. The configuration file is given in the standard output of firehol, thus `firehol helpme > /tmp/firehol.conf` will produce the output in `/tmp/firehol.conf`.

  The generated FireHOL configuration *must* be edited before use on your systems. You are required to take a number of decisions; the comments in the generated file will instruct you in the choices you must make.

## FILES

`/etc/firehol/firehol.conf`

## SEE ALSO

- •

  [firehol.conf(5)](/firehol.conf/5.md) - FireHOL configuration

- •

  [firehol-defaults.conf(5)](/firehol-defaults.conf/5.md) - control variables

- •

  FireHOL Website ⟨http://firehol.org/⟩\\c

- •

  FireHOL Online PDF Manual ⟨http://firehol.org/firehol-manual.pdf⟩\\c

- •

  FireHOL Online Documentation ⟨http://firehol.org/documentation/⟩\\c

## AUTHORS

FireHOL Team; Original man page by Marc Brockschmidt.