$Id: README 137 2006-01-04 08:31:23Z trappist $
IPKungFu version 0.6.0
Notes and configuration information on IPKungFu Please see the FAQ for troubleshooting.
IPKungFu man page available after installation
man ipkungfu
WHAT IS IPKUNGFU?
Ipkungfu is an iptables-based Linux firewall. The primary design goals are security, ease of use, and performance, in that order. It takes advantage of advanced features of iptables and the Linux kernel. Ipkungfu can handle a wide array of configurations, and supports Internet connection sharing, multiple virtual hosts, IP forwarding, IP masquerading, configurable logging, string matching and much more. It is designed with both the novice and the expert in mind with its simple configuration interface.
WHO SHOULD USE IPKUNGFU?
Anyone who wishes to simplify the creation of an iptables-based firewall. Additionally, anyone who would like a simple method of configuring a Linux machine to share its Internet connection.
HOW DOES IT WORK?
It takes configuration directives from the files in /etc/ipkungfu and uses them, along with some information gathered from your system, to build a firewall using iptables and sysctl. It is primarily an interface to iptables. which in turn is an interface to the Linux kernel's netfilter code.
WHERE CAN I GET THE LATEST VERSION?
IPKungFu can be obtained from http://freshmeat.net/ipkungfu Please send bug reports to bugreport@linuxkungfu.org Or, submit them to ipkungfu's development site: http://ipkungfu.ufsoft.org
I HAVE A QUESTION THAT IS NOT ANSWERED IN THIS DOCUMENT.
First read the FAQ, your question may be answered there. You may post questions at http://freshmeat.net/ipkungfu, you may be able to find me on IRC at: irc.freenode.net channel: #ipkungfu, or you can subscribe to our users mailing list:
To subscribe to the list, send a message to:
ipkungfu-users-subscribe@ufsoft.org
To remove your address from the list, just send a message to the address in
the "List-Unsubscribe" header of any list message.
If you haven't changed addresses since subscribing, you can also send a
message to:
ipkungfu-users-unsubscribe@ufsoft.org
HOW DO I RUN IPKUNGFU?
Running ipkungfu is done in a few simple steps. (as root)
- Download and unpack the source.
- Install per the installation instructions (./configure && make && sudo make install)
- Edit configuration files in /etc/ipkungfu to taste.
- Execute ipkungfu.
WHAT COMMAND LINE OPTIONS ARE AVAILABLE?
-t or --test
Test the configuration, listing some of the optional kernel
support installed, the interfaces in use, IP addresses,
whether or not you have chosen IP forwarding, IP masquerading,
subnet and ports you have chosen to allow.
-d or --disable
Disables the firewall and sets the default policies back to
ACCEPT. Internet connection sharing is not disabled.
-h or --help
Displays all options available to ipkungfu.
-v or --version
Displays the version number of ipkungfu and exits.
-l or --list
Displays the iptables rule sets and exits.
-c or --check
Check to see if ipkungfu is loaded and display if it is in
disable mode or panic mode if either.
-f or --flush
Flush all iptables rules and delete custom chains. This
completely takes down the firewall, and will also disable
Internet connection sharing.
--panic
Panic mode. All internal and external access is denied. Nothing
is allowed, in or out.
--quiet
Runs ipkungfu with no standard output.
--show-vars
Shows main configuration options (whether specified or
auto detected) and exits.
--failsafe
If ipkungfu fails, default policy for all builtin chains will
revert to ACCEPT. This essentially means the firewall will be
disabled if it fails. This is useful for working with ipkungfu
remotely, to prevent loss of access to the machine.
--no-caching
As of version 0.6.0, ipkungfu now supports rules caching support
which in case rules haven't changed, will make ipkungfu load way
faster. Passing this argument disables this feature.
WHAT DO I NEED TO RUN IPKUNGFU?
ipkungfu requires a Linux kernel of 2.4.x or higher. The following should be compiled into your kernel or as a module. Note that most Linux distributions already have much of this already, especially the required section. If you have other firewalls running, you should disable or uninstall them first to avoid conflict.
- Required
connection tracking
IP tables support
connection state match support
REJECT target support
full NAT
MASQUERADE target support
packet mangling
TOS target support
LOG (and/or ULOG) target support
multiple port match support
Highly recommended:
FTP protocol support
IRC protocol support
limit match support
REDIRECT target support
NAT of local connections
- Optional
ULOG target support
MIRROR target support
string match support
iplimit support
recent match support
psd match support
nth match support
tcp syncookie support
Currently IPKungFu does not support IPv6
INSTALLING IPKUNGFU
Installation of ipkungfu is designed to be as simple as possible. Unlike previous (and future) versions, ipkungfu does not ship with a configurator, and no configuration is done automatically at install time.
To install, download the ipkungfu-<version>.tgz file and run:
tar zxvf ipkungfu-<version>.tgz
Or if you have the ipkungfu-<version>.tar.bz2 file:
tar jxvf ipkungfu-<version>.tar.bz2
This will unpack and extract the files to a subdirectory named
ipkungfu-<version>
Then change into that directory:
cd ipkungfu-<version>
And then do:
./configure && make
And then su to root. (You must be root to be able to install) Then do:
make install
If this is the first time you install ipkungfu on your system also do:
make install-config
This will install the default configuration files. You MUST edit these files
before you run ipkungfu.
DO NOT run the above command if you have installed ipkungfu before and you
want you current configuration files, if you do, your old configuration files
will be overrriden.
CONFIGURATION FILES
There are several configuration files, each one corresponding to a specific
function or set of functions.
Advanced users or those with more complex networks will want to edit most or
all of these files. They are located in /etc/ipkungfu/ and are:
accept_hosts.conf : IP addresses of hosts or nets to always ACCEPT and optionally the ports they are allowed to access
advanced.conf : Configuration settings for advanced users.
custom.conf : Here you will find sample rules several sample rules already predefined. This is where you would add any custom rules you want applied to your firewall. This file is parsed first, before any other rules are added by ipkungfu, to ensure that none of ipkungfu's rules override the rules in this file.
deny_hosts.conf : You can list IP addresses/subnets:ports:protocols you wish to block completely. This file is parsed before accept_hosts.conf and takes precedence over it.
ipkungfu.conf : This is the main configuration file. Edit this file, if
nothing else. For most people, this is the only file that needs to be
edited to set up a decent firewall, with or without Internet connection
sharing.
WARNING: ALLOW_TCP_IN and ALLOW_UDP_IN are now deprecated and mantained only
for backward compatability. Now use services.conf.
log.conf : This file specifies what the firewall will log and the rate at which it is logged. By default, nearly all dropped packets are logged. To turn logging off on a particular item, change the 1 (log) to a 0 (don't log). The default location of the log on most systems is /var/log/syslog. Consult your syslogd configuration to find out where kernel logs are stored.
redirect.conf : Use this file to specify where certain traffic should be routed on the SAME machine. If you want to redirect ports that come in on one port, and should go to another, set them up here. There is a single entry here that is commented out by default- tcp:443:10000 which redirects incoming https traffic on port 443 to webmin on port 10000. Please see the file for more information.
vhosts.conf : If you have virtual hosts, (servers on machines behind your gateway), define the routing rules here. This file makes it possible to have servers behind the firewall, with private IP addresses, accessible from the Internet.
pre.conf : This is parsed and executed as a bash script prior to running ipkungfu.
post.conf : This is parsed and executed as a bash script after ipkungfu has completed execution.
services.conf : Here you keep all of your rules previously defined in ipkungfu.conf as ALLOW_TCP_IN and ALLOW_UDP_IN, plus more. Edit the file, it's self explanatory.
MANUALLY EDITING FILES
Most people, especially those with very simple configurations, will only need to edit /etc/ipkungfu/ipkungfu.conf if anything at all. As of 0.5.1 ipkungfu does a lot of detecting and guessing for the main configuration parameters unless you specify their values in ipkungfu.conf. This should work for most people. To go over the list of variables as ipkungfu knows them, run ipkungfu --show-vars. If anything looks wrong, edit the appropriate configuration file accordingly.
A "#" is a comment. When a line begins with #, the whole line is ignored. If you want enable an option in a configuration file that is commented out, simply remove the leading #. If you wish to remove an option, place a # in front of that line.
Note that anytime you edit a configuration file, you MUST rerun the script as outlined below in order for changes to take effect.
RUNNING THE SCRIPT
Now that you have ipkungfu configured, you must run the ipkungfu script as root to enable the firewall.
/usr/local/sbin/ipkungfu
or, if /usr/local/sbin is in your PATH, simply
ipkungfu
or, if your system is chkconfig-compatible, try
/etc/init.d/ipkungfu start
or
/etc/rc.d/init.d/ipkungfu start
You should see several lines explaining what is being done, unless you started ipkungfu using the init script.
If you would like ipkungfu to start at boot time, and your system is chkconfig compatable, then do (as root)
chkconfig --level 2345 ipkungfu on
This turns ipkungfu on for runlevels 2, 3, 4 and 5. Put whatever levels you like, with the obvious exceptions of levels 0, 1 or 6.
That's it! You can check to verify that the firewall is loaded:
ipkungfu -c or --check
You can also check to see if the firewall is running by
ipkungfu -l or --list
You should see several lines or pages of chains and rules. If you only see a few lines, or an error message, then the firewall is probably not enabled.
Any time you make a change to any of your configuration files, you MUST run ipkungfu again for your changes to take effect.
TROUBLESHOOTING
Most problems can be resolved by checking your settings in your configuration
files.
Many users overlook certain settings, so you may want to double-check them to
be sure.
Remember to run ipkungfu again (/usr/local/sbin/ipkungfu) after making any
changes to the configuration files (located in /etc/ipkungfu/).
Please see the FAQ for more troubleshooting issues and resolutions. If all
else fails, you can ask for help via IRC at: irc.freenode.net channel
#ipkungfu, or use the users mailing list show on the top of this document.
UNINSTALLING IPKUNGFU
Although uninstalling IPKungFu is not recommended, you may safely uninstall it.
- Run
ipkungfu --disable
Your iptables rules will be flushed and reset to the default ACCEPT policy.
Go to the directory where you unpacked ipkungfu and run:
make uninstall
If an error is outputed, do:
./configure && make uninstall