Free network firewall software for linux

links2world Firewall is a very simple tool writen in C, that helps you generate iptables rules for Linux 2.4.x and newer kernels. Released under GNU General Public License, it is very easy to configure and designed to run on hosts with one or more network interfaces.
Furthermore, they are able to generate iptables rulesets for one or maximum two network interfaces.
Most of the existing iptables script generators are shell scripts. You have to dig in and to look through entire script in order to customize and configure it for your needs.
On the other hand, links2world Firewall uses a very human readable configuration file that is very easy to understand and write. Still more, it does not matter if you have one, two, three or twenty network interfaces, links2world Firewall is able to generate statefull iptables rulesets able to control the packet flows between all the networks your machine is connected to.
Enhancements:
- minor fixes that solved compilation errors when using older compiles

InJoy Firewall is a flexible firewall security solution for businesses of any size. It offers preconfigured policy templates, including full customization options, IPSec VPN integration, gateway capabilities, intuitive management, access control, many documented deployment examples, and comprehensive documentation.

Without question, the Linux Operating System provides a proven and cost-effective platform, as well as a wealth of high-quality open source software. For business use, however, it often proves difficult to find supported linux firewall solutions that provide the required level of confidence, reliability and trust. With the InJoy Firewall™, businesses can benefit from Linux without having to give up the safety of a responsible vendor and a traditional business relationship.

Security as never before — the InJoy Firewall™ for Linux provides customers with next generation intrusion and anomaly detection. These technologies provides network administrators with the ultimate tools to keep track of network activity and eliminate Internet threats of any type.

As a busy and responsible network administrator, you will find great relief in the InJoy Firewall™. As the only Linux firewall, it is designed from the ground up to be self-contained, thus ensuring optimal performance and minimum impact from third-party problems. This means you dont have to worry about dependencies with Linux connectivity software, software libraries or kernel compilation.


Manage your remote Linux-based Firewall Server from your Windows-based desktop (or any other supported Operating Systems), using the intuitive InJoy firewall™ GUI. Linux users that prefer plain-text configuration can opt for that with the InJoy firewall™ as well.

The InJoy firewall™ works the same under all the supported operating systems, meaning you can deploy a complete and unified protection strategy throughout the business and effortlessly set up fully capable VPNs without having to worry about interoperability issues.

The InJoy firewall™ installs in minutes and can be prepared for distributed, company-wide deployment, using the same simple installation scripts everywhere.

TBFirewall provides a front-end for ipchains or iptables.

TBFirewall is a front-end created to control firewall rules. Its config files are constructed in the form of tables.

TBFirewall is designed to connect one or more local networks to another, forming an internetwork, but it can also run without problem in other network models.

Linux Firewall is a robust, well-designed firewall for Linux 2.4 based on netfilter/iptables. The Projectfiles.com Linux Firewall is the swiss army knife of Linux firewall software. Based on the netfilter-iptables tools, the firewall is a single shell executable written in bash with configuration options and basic documentation included in the same file. It is designed for use with all types of systems: workstations, routers, and servers, and includes advanced features for expert users and Internet Service Providers.

Here are some installation tips:

1. Download the latest rc.firewall [wget http://projectfiles.com/firewall/rc.firewall]
2. Edit the options at the beginning of the file with your favorite text editor. The script comes pre-configured to deny all incoming connections. This is suitable for a typical workstation installation. Refer to the configuration page for in depth explanation of available options.
3. Make the script executable [chmod +x ./rc.firewall]
4. Become root [su]
5. Run the script [./rc.firewall]
6. After you verify that the firewall runs without errors, you may want it to be run automatically on boot. To accomplish this, move the script to the appropriate startup script directory for your distribution [/etc/rc.d/ for Slackware, /etc/init.d/ for Gentoo] and add the following lines in your startup scripts at some point after your ethernet interfaces are configured [for example /etc/rc.d/rc.local for Slackware, and /etc/conf.d/local.start for Gentoo].

Slackware
if [ -x /etc/rc.d/rc.firewall ]; then
/etc/rc.d/rc.firewall
fi
Gentoo
if [ -x /etc/init.d/rc.firewall ]; then
/etc/init.d/rc.firewall
fi

See forum for alternate installation methods.
7. If you are using this firewall on a machine to which you do not have physical access, but can reboot remotely (for example a collocated server or a Linux router at a computer illiterate friends house), you might want to think about putting in a short delay between the time the machine boots and the initialization of the firewall. This would give you a chance to log in and disable the firewall [chmod -x] if something goes wrong. A good example might be if you have the script configured to allow you to connect from a specific remote IP address and your address changes. If you choose to implement this idea, it can be done with the following code in rc.local:

if [ -x /etc/rc.d/rc.firewall ]; then
sleep 30 && /etc/rc.d/rc.firewall | logger -t rc.firewall &
echo "Firewall init in 30 seconds. Check syslog for results."
fi

NetSecL-Firewall is an iptables script that protects against stealth scans, port scans, OS fingerprints, and other types of scanning.

NetSecL-Firewall iptables script is the default firewall in the NetSecL Linux distribution.

Network Configurator is a network configuration tool.
Network Configurator is user-level tool that aims to make network configuration more easy. It have command line and GTK+ interface.
Supported network types:
- Ethernet
- PPPoE
- PPTP
- Wi-Fi (no WEP and WPA for now)
- dialup

UTIN Firewall script project is a script for Linux 2.4.x and iptables.

###########
# Configuration options, these will speed you up getting this script to
# work with your own setup.

#
# your LANs IP range and localhost IP. /24 means to only use the first 24
# bits of the 32 bit IP adress. the same as netmask 255.255.255.0
#
# INET_IP is used by me to allow myself to do anything to myself, might
# be a security risc but sometimes I want this. If you dont have a static
# IP, I suggest not using this option at all for now but its still
# enabled per default and will add some really nifty security bugs for all
# those who skips reading the documentation=)

LAN_IP="192.168.0.2"
LAN_BCAST_ADRESS="192.168.0.255"
LAN_IFACE="eth1"

LO_IFACE="lo"
LO_IP="127.0.0.1"

INET_IP="194.236.50.155"
INET_IFACE="eth0"

IPTABLES="/usr/local/sbin/iptables"

#########
# Load all required IPTables modules
#

#
# Needed to initially load modules
#
/sbin/depmod -a

#
# Adds some iptables targets like LOG, REJECT and MASQUARADE.
#
/sbin/modprobe ipt_LOG
#/sbin/modprobe ipt_REJECT
/sbin/modprobe ipt_MASQUERADE

#
# Support for owner matching
#
#/sbin/modprobe ipt_owner

#
# Support for connection tracking of FTP and IRC.
#
#/sbin/modprobe ip_conntrack_ftp
#/sbin/modprobe ip_conntrack_irc

#
# Enable ip_forward, this is critical since it is turned off as defaul in
# Linux.
#

echo "1" > /proc/sys/net/ipv4/ip_forward

#
# Dynamic IP users:
#
#echo "1" > /proc/sys/net/ipv4/ip_dynaddr

#
# Enable simple IP Forwarding and Network Address Translation
#

$IPTABLES -t nat -A POSTROUTING -o $INET_IFACE -j SNAT --to-source $INET_IP

#
# Set default policies for the INPUT, FORWARD and OUTPUT chains
#

$IPTABLES -P INPUT DROP
$IPTABLES -P OUTPUT DROP
$IPTABLES -P FORWARD DROP

#
# bad_tcp_packets chain
#
# Take care of bad TCP packets that we dont want.
#

$IPTABLES -N bad_tcp_packets
$IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j LOG
--log-prefix "New not syn:"
$IPTABLES -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j DROP

#
# Do some checks for obviously spoofed IPs
#

$IPTABLES -A bad_tcp_packets -i $INET_IFACE -s 192.168.0.0/16 -j DROP
$IPTABLES -A bad_tcp_packets -i $INET_IFACE -s 10.0.0.0/8 -j DROP
$IPTABLES -A bad_tcp_packets -i $INET_IFACE -s 172.16.0.0/12 -j DROP
$IPTABLES -A bad_tcp_packets -i $LAN_IFACE ! -s 192.168.0.0/16 -j DROP

#
# Bad TCP packets we dont want
#

$IPTABLES -A FORWARD -p tcp -j bad_tcp_packets

#
# Accept the packets we actually want to forward between interfaces.
#

$IPTABLES -A FORWARD -p tcp --dport 21 -i $LAN_IFACE -j ACCEPT
$IPTABLES -A FORWARD -p tcp --dport 80 -i $LAN_IFACE -j ACCEPT
$IPTABLES -A FORWARD -p tcp --dport 110 -i $LAN_IFACE -j ACCEPT

$IPTABLES -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT
$IPTABLES -A FORWARD -m limit --limit 3/minute --limit-burst 3 -j LOG
--log-level DEBUG --log-prefix "IPT FORWARD packet died: "


#
# Create separate chains for ICMP, TCP and UDP to traverse
#

$IPTABLES -N icmp_packets
$IPTABLES -N tcp_packets
$IPTABLES -N udpincoming_packets

#
# The allowed chain for TCP connections
#

$IPTABLES -N allowed
$IPTABLES -A allowed -p TCP --syn -j ACCEPT
$IPTABLES -A allowed -p TCP -m state --state ESTABLISHED,RELATED
-j ACCEPT
$IPTABLES -A allowed -p TCP -j DROP

#
# ICMP rules
#

# Changed rules totally
$IPTABLES -A icmp_packets -p ICMP -s 0/0 --icmp-type 8 -j ACCEPT
$IPTABLES -A icmp_packets -p ICMP -s 0/0 --icmp-type 11 -j ACCEPT

#
# TCP rules
#

$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 21 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 22 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 80 -j allowed
$IPTABLES -A tcp_packets -p TCP -s 0/0 --dport 113 -j allowed

#
# UDP ports
#

$IPTABLES -A udpincoming_packets -p UDP -s 0/0 --source-port 53 -j ACCEPT
$IPTABLES -A udpincoming_packets -p UDP -s 0/0 --source-port 123 -j ACCEPT
$IPTABLES -A udpincoming_packets -p UDP -s 0/0 --source-port 2074 -j ACCEPT
$IPTABLES -A udpincoming_packets -p UDP -s 0/0 --source-port 4000 -j ACCEPT

#
# INPUT chain
#
# Bad TCP packets we dont want
#

$IPTABLES -A INPUT -p tcp -j bad_tcp_packets

#
# Rules for incoming packets from anywhere
#

$IPTABLES -A INPUT -p ICMP -j icmp_packets
$IPTABLES -A INPUT -p TCP -j tcp_packets
$IPTABLES -A INPUT -p UDP -j udpincoming_packets

#
# Rules for special networks not part of the Internet
#

$IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $LO_IP -j ACCEPT
$IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $LAN_IP -j ACCEPT
$IPTABLES -A INPUT -p ALL -i $LO_IFACE -s $INET_IP -j ACCEPT
$IPTABLES -A INPUT -p ALL -d $INET_IP -m state --state ESTABLISHED,RELATED
-j ACCEPT
$IPTABLES -A INPUT -m limit --limit 3/minute --limit-burst 3
-j LOG --log-level DEBUG --log-prefix "IPT INPUT packet died: "

#
# OUTPUT chain
#
#
# Bad TCP packets we dont want
#

$IPTABLES -A OUTPUT -p tcp -j bad_tcp_packets


$IPTABLES -A OUTPUT -p ALL -s $LO_IP -j ACCEPT
$IPTABLES -A OUTPUT -p ALL -s $LAN_IP -j ACCEPT
$IPTABLES -A OUTPUT -p ALL -s $INET_IP -j ACCEPT
$IPTABLES -A OUTPUT -m limit --limit 3/minute --limit-burst 3
-j LOG --log-level DEBUG --log-prefix "IPT OUTPUT packet died: "