Ubuntu Manpage: sanewall - an easy to use but powerful iptables stateful firewall

NAME

       sanewall - an easy to use but powerful iptables stateful firewall

SYNOPSIS

       sanewall

       sudo -E sanewall panic [IP]

       sanewall command [-- conf-arg...]

       sanewall CONFIGFILE [start | debug | try] [-- conf-arg...]

DESCRIPTION

       Running sanewall invokes iptables(8) to manipulate your firewall.

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

       When given CONFIGFILE, sanewall will use the named file instead of
       /etc/sanewall/sanewall.conf as its configuration. If no command is given, sanewall 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) syntax e.g. $1, $2, etc.

       Sanewall is a fork of FireHOL[1]. existing FireHOL configurations should be compatible
       with Sanewall, but please see the section called “COMPATIBILITY” for any differences in
       behaviour.

PANIC

       To block all communication, invoke sanewall with the panic command.

       Sanewall removes all rules from the running firewall and then DROPs all traffic on all
       iptables 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, Sanewall checks for the existence of the SSH_CLIENT shell
       environment variable, which is set by ssh. If it finds this, then panic mode will allow
       the established SSH connection specified in this variable to operate.

           Note
           In order for Sanewall to see the environment variable you must ensure that it is
           preserved. For sudo use the -E and for su 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 configuration from /etc/sanewall/sanewall.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 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
Starts the Sanewall firewall only if it is not already active. It does not detect a
modified configuration file, only verifies that Sanewall has been started in the past
and not stopped yet.

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

save
Start the firewall and then save it using /sbin/iptables-save to
/etc/sysconfig/iptables.

The required kernel modules are saved to an executable shell script
/var/spool/sanewall/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 Sanewall will work.

This is because as part of starting a firewall, Sanewall 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, Sanewall shows the
generated iptables statements.

explain
Enters an interactive mode where Sanewall accepts normal configuration commands and
presents the generated iptables commands for each of them, together with some
reasoning for its purpose

Additionally, Sanewall 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 Sanewall configuration needed for the current machine.

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

The generated Sanewall 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.

COMPATIBILITY

       Sanewall should be largely compatible with all existing FireHOL configurations.

       If you are using any variable starting "FIREHOL_" in your configuration, you will need to
       rename it to "SANEWALL_". See control variables: sanewall-variables(5) for a list of all
       variables used to control Sanewall.

       In addition the default values of SANEWALL_*_ACTIVATION_POLICY, for each of INPUT, OUTPUT
       and FORWARD have been changed to DROP. See the entries under control variables:
       sanewall-variables(5) for details and how to obtain the original behaviour.

FILES

           /etc/sanewall/sanewall.conf

AUTHORS

       Sanewall Team

       Sanewall is heavily based on FireHOL by Costa Tsaouis
       Original man page by Marc Brockschmidt

COPYRIGHT

NOTES

        1. FireHOL
           http://firehol.sourceforge.net/

        2. Sanewall Online Documentation
           http://www.sanewall.org/