Anatomy of Shorewall 4.5
Tom
Eastep
2007
2009
2012
Thomas M. Eastep
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version
1.2 or any later version published by the Free Software Foundation; with
no Invariant Sections, with no Front-Cover, and with no Back-Cover
Texts. A copy of the license is included in the section entitled
GNU Free Documentation
License
.
Products
Shorewall 4.5 consists of six packages.
Shorewall Core. This package
contains the core Shorewall shell libraries and is required to install
any of the other packages.
Shorewall. This package must be
installed on at least one system in your network. It contains
everything needed to create an IPv4 firewall.
Shorewall6. This package
requires the Shorewall package and adds those components needed to
create an IPv6 fireawall.
Shorewall-lite. Shorewall
allows for central administration of multiple IPv4 firewalls through
use of Shorewall lite. The full Shorewall product is installed on a
central administrative system where compiled Shorewall scripts are
generated. These scripts are copied to the firewall systems where they
run under the control of Shorewall-lite.
Shorewall6-lite. Shorewall
allows for central administration of multiple IPv4 firewalls through
use of Shorewall lite. The full Shorewall product is installed on a
central administrative system where compiled Shorewall scripts are
generated. These scripts are copied to the firewall systems where they
run under the control of Shorewall-lite.
Shorewall-init. An add-on to any of the above packages that
allows the firewall state to be altered in reaction to interfaces
coming up and going down. Where Upstart is not being used, this
package can also be configured to place the firewall in a safe state
prior to bringing up the network interfaces.
Shorewall
The Shorewall package includes a large number of files which are
installed in /sbin, /usr/share/shorewall, /etc/shorewall,
/etc/init.d and /var/lib/shorewall/. These are described in
the sub-sections that follow.
/sbin
The /sbin/shorewall shell program is used to
interact with Shorewall. See shorewall(8).
/usr/share/shorewall
The bulk of Shorewall is installed here.
action.template - template file for
creating actions.
action.* - standard Shorewall
actions.
actions.std - file listing the standard
actions.
compiler.pl - The configuration compiler
perl program.
configfiles - A
directory containing configuration files to copy to create a Shorewall-lite export
directory.
configpath - A file
containing distribution-specific path assignments.
firewall - A shell program that handles
the add and delete commands
(see shorewall(8)). It
also handles the stop and
clear commands when there is no current compiled
firewall script on the system.
functions - A symbolic
link to lib.base that provides for
compatibility with older versions of Shorewall.
init - A symbolic link to
the init script (usually
/etc/init.d/shorewall).
lib.* - Shell function libraries used by
the other shell programs.
Macros/* - The standard Shorewall macros.
modules.* - File that drives the loading
of Netfilter kernel modules. May be overridden by
/etc/shorewall/modules.
prog.* - Shell program fragments used as
input to the compiler.
Shorewall - Directory
containing the Shorewall Perl modules used by the compiler.
version - A file containing the currently
install version of Shorewall.
wait4ifup - A shell program that extension scripts can
use to delay until a network interface is available.
/etc/shorewall
This is where the modifiable IPv4 configuration files are
installed.
/etc/init.d or /etc/rc.d (depends on distribution)
An init script is installed here. Depending on the distribution,
it is named shorewall or
rc.firewall.
/var/lib/shorewall
Shorewall doesn't install any files in this directory but rather
uses the directory for storing state information. This directory may be
relocated using shorewall-vardir(5).
.iptables-restore-input - The file passed
as input to the iptables-restore program to initialize the firewall
during the last start or
restart command (see shorewall(8)).
.modules - The contents of the modules
file used during the last start or
restart command (see shorewall(8) for command
information).
.modulesdir - The MODULESDIR setting
(shorewall.conf(5)) at the
last start or restart.
nat - This unfortunately-named file
records the IP addresses added by ADD_SNAT_ALIASES=Yes and
ADD_IP_ALIASES=Yes in shorewall.conf(5).
proxyarp - Records the arp entries added
by entries in shorewall-proxyarp(5).
.refresh - The shell program that
performed the last successful refresh
command.
.restart - The shell program that
performed the last successful restart
command.
restore - The default shell program used
to execute restore commands.
.restore - The shell program that
performed the last successful refresh, restart or
start command.
save - File created by the
save command and used to restore the dynamic
blacklist during start/restart.
.start - The shell program that performed
the last successful start command.
state - Records the current firewall
state.
zones - Records the current zone
contents.
Shorewall6
Shorewall6 installs its files in a number of directories:
/sbin
The /sbin/shorewall6 shell program is used to
interact with Shorewall6. See shorewall6(8).
/usr/share/shorewall6
The bulk of Shorewall6 is installed here.
action.template - template file for
creating actions.
action.* - standard Shorewall
actions.
actions.std - file listing the standard
actions.
configfiles - A
directory containing configuration files to copy to create a Shorewall6-lite export
directory.
configpath - A file
containing distribution-specific path assignments.
firewall - A shell program that handles
the add and delete commands
(see shorewall(8)). It
also handles the stop and
clear commands when there is no current compiled
firewall script on the system.
functions - A symbolic
link to lib.base that provides for
compatibility with older versions of Shorewall.
lib.* - Shell function libraries used by
the other shell programs.
Macros/* - The standard Shorewall6 macros.
modules - File that drives the loading of
Netfilter kernel modules. May be overridden by
/etc/shorewall/modules.
version - A file containing the currently
install version of Shorewall.
wait4ifup - A shell program that extension scripts can
use to delay until a network interface is available.
/etc/shorewall6
This is where the modifiable IPv6 configuration files are
installed.
/var/lib/shorewall6
Shorewall6 doesn't install any files in this directory but rather
uses the directory for storing state information. This directory may be
relocated using shorewall-vardir(5).
.ip6tables-restore-input - The file
passed as input to the ip6tables-restore program to initialize the
firewall during the last start or
restart command (see shorewall6(8)).
.modules - The contents of the modules
file used during the last start or
restart command (see shorewall(8) for command
information).
.modulesdir - The MODULESDIR setting
(shorewall.conf(5)) at the
last start or restart.
.refresh - The shell program that
performed the last successful refresh
command.
.restart - The shell program that
performed the last successful restart
command.
restore - The default shell program used
to execute restore commands.
.restore - The shell program that
performed the last successful refresh, restart or
start command.
save - File created by the
save command and used to restore the dynamic
blacklist during start/restart.
.start - The shell program that performed
the last successful start command.
state - Records the current firewall
state.
zones - Records the current zone
contents.
Shorewall-lite
The Shorewall-lite product includes files installed in /sbin, /usr/share/shorewall-lite, /etc/shorewall-lite,
/etc/init.d and /var/lib/shorewall-lite/. These are described
in the sub-sections that follow.
/sbin
The /sbin/shorewall-lite shell program is use
to interact with Shorewall lite. See shorewall-lite(8).
/etc/init.d or /etc/rc.d (depends on distribution)
An init script is installed here. Depending on the distribution,
it is named shorewall-lite or
rc.firewall.
/etc/shorewall-lite
This is where the modifiable configuration files are
installed.
/usr/share/shorewall-lite
The bulk of Shorewall-lite is installed here.
configpath - A file
containing distribution-specific path assignments.
functions - A symbolic
link to lib.base that provides for
compatibility with older versions of Shorewall.
lib.base - Shell function librarie used
by the other shell programs. This is a thin wrapper around
/usr/share/shorewall/lib.base.
modules* - Files that drive the loading
of Netfilter kernel modules. May be overridden by
/etc/shorewall-lite/modules.
shorecap - A shell program used for
generating capabilities files. See the Shorewall-lite
documentation.
version - A file containing the currently
install version of Shorewall.
wait4ifup - A shell program that extension scripts can
use to delay until a network interface is available.
/var/lib/shorewall-lite
Shorewall-lite doesn't install any files in this directory but
rather uses the directory for storing state information. This directory
may be relocated using shorewall-lite-vardir(5).
firewall - Compiled shell script
installed by running the load or reload command on the
administrative system (see shorewall(8)).
firewall.conf - Digest of the
shorewall.conf file used to compile the firewall script on the
administrative system.
.iptables-restore-input - The file passed
as input to the iptables-restore program to initialize the firewall
during the last start or
restart command (see shorewall-lite(8)).
.modules - The contents of the modules
file used during the last start or
restart command (see shorewall-lite(8) for
command information).
.modulesdir - The MODULESDIR setting
(shorewall.conf(5)) at the
last start or restart.
nat - This unfortunately-named file
records the IP addresses added by ADD_SNAT_ALIASES=Yes and
ADD_IP_ALIASES=Yes in shorewall.conf(5).
proxyarp - Records the arp entries added
by entries in shorewall-proxyarp(5).
.refresh - The shell program that
performed the last successful refresh
command.
.restart - The shell program that
performed the last successful restart
command.
restore - The default shell program used
to execute restore commands.
.restore - The shell program that
performed the last successful refresh, restart or
start command.
save - File created by the
save command and used to restore the dynamic
blacklist during start/restart.
.start - The shell program that performed
the last successful start command.
state - Records the current firewall
state.
zones - Records the current zone
contents.
Shorewall6-lite
The Shorewall6-lite product includes files installed in /sbin, /usr/share/shorewall6-lite, /etc/shorewall6-lite,
/etc/init.d and /var/lib/shorewall6-lite/. These are
described in the sub-sections that follow.
/sbin
The /sbin/shorewall6-lite shell program is
use to interact with Shorewall lite. See shorewall6-lite(8).
/etc/init.d or /etc/rc.d (depends on distribution)
An init script is installed here. Depending on the distribution,
it is named shorewall6-lite or
rc.firewall.
/etc/shorewall6-lite
This is where the modifiable configuration files are
installed.
/usr/share/shorewall6-lite
The bulk of Shorewall-lite is installed here.
configpath - A file
containing distribution-specific path assignments.
functions - A symbolic
link to lib.base that provides for
compatibility with older versions of Shorewall.
lib.base - Shell function librarie used
by the other shell programs. This is a thin wrapper around
/usr/share/shorewall/lib.base.
modules* - Files that drive the loading
of Netfilter kernel modules. May be overridden by
/etc/shorewall-lite/modules.
shorecap - A shell program used for
generating capabilities files. See the Shorewall-lite
documentation.
version - A file containing the currently
install version of Shorewall.
wait4ifup - A shell program that extension scripts can
use to delay until a network interface is available.
/var/lib/shorewall6-lite
Shorewall6-lite doesn't install any files in this directory but
rather uses the directory for storing state information. This directory
may be relocated using shorewall-lite-vardir(5).
firewall - Compiled shell script
installed by running the load or reload command on the
administrative system (see shorewall6(8)).
firewall.conf - Digest of the
shorewall.conf file used to compile the firewall script on the
administrative system.
.ip6tables-restore-input - The file
passed as input to the ip6tables-restore program to initialize the
firewall during the last start or
restart command (see shorewall-lite(8)).
.modules - The contents of the modules
file used during the last start or
restart command (see shorewall-lite(8) for
command information).
.modulesdir - The MODULESDIR setting
(shorewall.conf(5)) at the
last start or restart.
.refresh - The shell program that
performed the last successful refresh
command.
.restart - The shell program that
performed the last successful restart
command.
restore - The default shell program used
to execute restore commands.
.restore - The shell program that
performed the last successful refresh, restart or
start command.
save - File created by the
save command and used to restore the dynamic
blacklist during start/restart.
.start - The shell program that performed
the last successful start command.
state - Records the current firewall
state.
zones - Records the current zone
contents.