Difference between revisions of "Firewalls"

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[[Category:Networking (English)]]
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[[Category:Networking]]
[[Category:Security (English)]]
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[[Category:Security]]
{{i18n|Firewalls}}
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[[es:Firewalls]]
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[[it:Firewalls]]
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[[sr:Firewalls]]
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[[sv:Brandväggar]]
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{{Poor writing|convert to [[Template:App]]}}
  
 
A firewall is a system designed to prevent unauthorized access to or from a private network (which could be just one machine).  Firewalls can be implemented in only hardware or software, or a combination of both.  Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets.  All messages entering or leaving the intranet pass through the firewall, which examines each message and allows, proxys, or denies the traffic based on specified security criteria.
 
A firewall is a system designed to prevent unauthorized access to or from a private network (which could be just one machine).  Firewalls can be implemented in only hardware or software, or a combination of both.  Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets.  All messages entering or leaving the intranet pass through the firewall, which examines each message and allows, proxys, or denies the traffic based on specified security criteria.
  
There is a nice list of firewalls [http://wiki.debian.org/Firewalls here].
+
The firewalls listed in this article are overwhelmingly based on the [[iptables]] program. Consider configuring the iptables process yourself according to its wiki page (listed below) to keep to the [[The Arch Way]].
  
 
There are many posts on the forums about different firewall apps and scripts so here they all are condensed into one page - please add your comments about each firewall, especially ease of use and a security check at [https://www.grc.com/x/ne.dll?bh0bkyd2 Shields Up].
 
There are many posts on the forums about different firewall apps and scripts so here they all are condensed into one page - please add your comments about each firewall, especially ease of use and a security check at [https://www.grc.com/x/ne.dll?bh0bkyd2 Shields Up].
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{{Note|Checks at Shields Up are only a valid measure of your router should you have one in the LAN.  To accurately evaluate a software firewall, one needs to directly connect the box to the cable modem.}}
 
{{Note|Checks at Shields Up are only a valid measure of your router should you have one in the LAN.  To accurately evaluate a software firewall, one needs to directly connect the box to the cable modem.}}
  
==[[iptables]]==
+
==Firewall Guides & Tutorials==
The Linux kernel itself has very powerful firewall called iptables. Other firewalls are usually just frontends.
+
:* [[Simple Stateful Firewall]]: Setting up a comprehensive firewall with iptables.
  
See the [[iptables|iptables article]] for more information.
+
:* [[Uncomplicated Firewall]], the wiki page for the simple iptables frontend, '''ufw''', provides a nice tutorial for a basic configuration.
  
'''More info:'''
+
:* [[Router]] Setup Guide. A tutorial for turning a computer into an internet gateway/router. It focuses on security and configuring your gateway to have as few insecure holes to the internet as possible.
*[[Simple_stateful_firewall_HOWTO|Simple stateful firewall]]
+
 
*[[Router]]
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====External Firewall Tutorials====
*man iptables http://unixhelp.ed.ac.uk/CGI/man-cgi?iptables+8
+
 
*http://tldp.org/HOWTO/Masquerading-Simple-HOWTO/
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:* http://www.frozentux.net/documents/iptables-tutorial/ A complete and simple tutorial to iptables
*http://netfilter.org/documentation/HOWTO/NAT-HOWTO.html
+
 
*http://www.frozentux.net/documents/iptables-tutorial/
+
:* http://tldp.org/HOWTO/Masquerading-Simple-HOWTO/IP Masq is a form of Network Address Translation or NAT that allows internally networked computers that do not have one or more registered Internet IP addresses to have the ability to communicate to the Internet via your Linux boxes single Internet IP address.
 +
 
 +
:* http://tldp.org/HOWTO/Masquerading-Simple-HOWTO/ Masquerading, transparent proxying, port forwarding, and other forms of Network Address Translations with the 2.4 Linux Kernels.
  
 
==iptables front-ends==
 
==iptables front-ends==
 +
===iptables===
 +
* {{App|[[Iptables]]|A powerful firewall built into the Linux kernel that is part of the [[Wikipedia:Netfilter|Netfilter]] project. Most firewalls, as described in this section below, are usually just front-ends.|http://www.netfilter.org/projects/iptables/index.html|{{Pkg|iptables}}}}
 +
 +
Also see the man pages: ({{Ic|man iptables}}) – http://unixhelp.ed.ac.uk/CGI/man-cgi?iptables+8
 +
 
===Arno's Firewall===
 
===Arno's Firewall===
 
[http://rocky.eld.leidenuniv.nl/ Arno's IPTABLES Firewall Script] is a secure firewall for both single and multi-homed machines.
 
[http://rocky.eld.leidenuniv.nl/ Arno's IPTABLES Firewall Script] is a secure firewall for both single and multi-homed machines.
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*protection against SYN/ICMP flooding
 
*protection against SYN/ICMP flooding
 
*extensive user definable logging with rate limiting to prevent log flooding
 
*extensive user definable logging with rate limiting to prevent log flooding
*all IP protocols and VPNs such as IPSec
+
*all IP protocols and VPNs such as IPsec
 
*plugin support to add extra features.
 
*plugin support to add extra features.
  
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[http://firehol.sourceforge.net/ FireHOL] is a language to express firewalling rules, not just a script that produces some kind of a firewall. It makes building even sophisticated firewalls easy - the way you want it. The result is actually iptables rules.
 
[http://firehol.sourceforge.net/ FireHOL] is a language to express firewalling rules, not just a script that produces some kind of a firewall. It makes building even sophisticated firewalls easy - the way you want it. The result is actually iptables rules.
  
{{Codeline|firehol}} is available in the community repository.
+
{{Pkg|firehol}} is available in the [[Official Repositories|official repositories]].
  
 
===Firetable===
 
===Firetable===
[http://projects.leisink.org/firetable Firetable] is an iptables-based firewall with "human readable" syntax.
+
[http://projects.leisink.net/firetable Firetable] is an iptables-based firewall with "human readable" syntax.
  
{{Codeline|firetable}} is available in [[AUR]].
+
{{AUR|firetable}} is available in the [[Arch User Repository|AUR]].
 
+
===gShield===
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[http://muse.linuxmafia.org/gshield/ gShield] is a really simple iptables configuration system. (Nothing to do with gnome) Easy to configure, blocks everything not needed (almost) by default. Controlled by only one configuration file. It gave me all stealth on grc.com
+
 
+
{{Codeline|gshield}} is available in [[AUR]].
+
 
+
Pros:
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*Easy to configure
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*Only one configuration file
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*Will give you a iptables configuration, which is the best firewall
+
Cons:
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*No GUI
+
  
 
===Shorewall===
 
===Shorewall===
 
[http://www.shorewall.net/ The Shoreline Firewall], more commonly known as "Shorewall", is high-level tool for configuring Netfilter. You describe your firewall/gateway requirements using entries in a set of configuration files. Shorewall reads those configuration files and with the help of the iptables utility, Shorewall configures Netfilter to match your requirements. Shorewall can be used on a dedicated firewall system, a multi-function gateway/router/server or on a standalone GNU/Linux system. Shorewall does not use Netfilter's ipchains compatibility mode and can thus take advantage of Netfilter's connection state tracking capabilities.
 
[http://www.shorewall.net/ The Shoreline Firewall], more commonly known as "Shorewall", is high-level tool for configuring Netfilter. You describe your firewall/gateway requirements using entries in a set of configuration files. Shorewall reads those configuration files and with the help of the iptables utility, Shorewall configures Netfilter to match your requirements. Shorewall can be used on a dedicated firewall system, a multi-function gateway/router/server or on a standalone GNU/Linux system. Shorewall does not use Netfilter's ipchains compatibility mode and can thus take advantage of Netfilter's connection state tracking capabilities.
  
{{Codeline|shorewall}} is available in the {{Codeline|community}} repository.
+
{{Pkg|shorewall}} is available in the [[Official Repositories|official repositories]].
 
+
===uruk===
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[http://mdcc.cx/uruk/ uruk] loads an rc file, which defines network service access policy, and invokes iptables to set up firewall rules implementing this policy.
+
 
+
uruk is not available in any Arch Linux repository.
+
  
 
===ufw===
 
===ufw===
ufw (uncomplicated firewall) is a simple frontend for iptables and is available in [community].  The next two sections are simply high-level explanations and examples.  Users are encouraged to consult the [https://help.ubuntu.com/community/UFW Ubuntu Firewall Help] page for additional details.
+
ufw (uncomplicated firewall) is a simple front-end for iptables and is available in the [[Official Repositories|official repositories]].
 
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====Basic Configuration====
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A very simplistic configuration which will deny all by default, allow any protocol from inside a 192.168.0.1-192.168.0.255 LAN, and allow incoming Deluge and SSH traffic from anywhere:
+
 
+
# ufw default deny
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# ufw allow from 192.168.0.0/24
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# ufw allow Deluge
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# ufw allow SSH
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The next line is only need ''once'' the first time you install the package.  From there on out, control it via the standard rc.d script (i.e. rc.d start ufw):
+
 
+
# ufw enable
+
 
+
Finally, query the rules being applied via the status command:
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# ufw status
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<pre>Status: active
+
 
+
To                        Action      From
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--                        ------      ----
+
Anywhere                  ALLOW      192.168.0.0/24
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Deluge                    ALLOW      Anywhere
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SSH                        ALLOW      Anywhere
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</pre>
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==== Adding Other Applications ====
+
 
+
The PKG comes with some defaults based on the default ports of many common daemons and programs.  Inspect the options by looking in the /etc/ufw/applications.d directory or by listing them in the program itself:
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# ufw app list
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+
If users are running any of the applications on a non-standard port, it is recommended to simply make {{Filename|/etc/ufw/applications.d/custom}} containing the needed data using the defaults as a guide.
+
 
+
{{Warning|If users modify any of the PKG provided rule sets, these will be overwritten the first time the ufw package is updated.  This is why custom app definitions need to reside in a non-PKG file as recommended above!}}
+
 
+
Example, deluge with custom ports that range from 20202-20205:
+
 
+
[Deluge-my]
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title=Deluge
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description=Deluge BitTorrent client
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ports=20202:20205/tcp
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Should you require to define both tcp and udp ports for the same application, simply separate them with a pipe as shown: this app opens tcp ports 10000-10002 and udp port 10003
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ports=10000:100002/tcp|10003/udp
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{{Note|Whenever rules are added or deleted, ufw must be restarted to reload the changes.}}
+
 
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==== Deleting Applications ====
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Drawing on the Deluge/Deluge-my example above, the following will remove the standard Deluge rules and replace them with the Deluge-my rules from the above example:
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# ufw delete allow Deluge
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# ufw allow Deluge-my
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+
Query the result via the status command:
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# ufw status
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<pre>Status: active
+
  
To                        Action      From
+
See [[Uncomplicated Firewall]] for more information.
--                        ------      ----
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Anywhere                  ALLOW      192.168.0.0/24
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SSH                        ALLOW      Anywhere
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Deluge-my                  ALLOW      Anywhere
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</pre>
+
  
 
===Vuurmuur===
 
===Vuurmuur===
[http://www.vuurmuur.org/ Vuurmuur] Vuurmuur is a powerful firewall manager built on top of iptables. It has a simple and easy to learn configuration that allows both simple and complex configurations. The configuration can be fully configured through an ncurses GUI, which allows secure remote administration through SSH or on the console. Vuurmuur supports traffic shaping, has powerful monitoring features, which allow the administrator to look at the logs, connections and bandwidth usage in realtime.
+
[http://www.vuurmuur.org/ Vuurmuur] Vuurmuur is a powerful firewall manager built on top of iptables. It has a simple and easy to learn configuration that allows both simple and complex configurations. The configuration can be fully configured through an {{Pkg|ncurses}} GUI, which allows secure remote administration through SSH or on the console. Vuurmuur supports traffic shaping, has powerful monitoring features, which allow the administrator to look at the logs, connections and bandwidth usage in realtime.
  
{{Codeline|Vuurmuur}} and is available in [[AUR]].
+
{{AUR|Vuurmuur}} is available in the [[Arch User Repository|AUR]].
  
 
==iptables GUIs==
 
==iptables GUIs==
 
===Firestarter===
 
===Firestarter===
[http://www.fs-security.com/ Firestarter] is a good GUI for iptables, it has the ability to use both white and black lists for regulating traffic, it is very simple and easy to use, with good documentation available on their website.
+
[http://www.fs-security.com/ Firestarter] is a good GUI for iptables writen on GTK2, it has the ability to use both white and black lists for regulating traffic, it is very simple and easy to use, with good documentation available on their website.
  
Firestarter has gnome dependencies and is available in [[AUR]].
+
{{AUR|Firestarter}} has [[GNOME]] dependencies and is available in the [[Arch User Repository|AUR]].
  
 
===Guarddog===
 
===Guarddog===
 
[http://www.simonzone.com/software/guarddog/ Guarddog] is a really easy to use GUI for configuring iptables. After setting up a basic desktop configuration it passes all Shields Up tests perfectly.
 
[http://www.simonzone.com/software/guarddog/ Guarddog] is a really easy to use GUI for configuring iptables. After setting up a basic desktop configuration it passes all Shields Up tests perfectly.
  
Guarddog requires kdelibs3 and is available in the [[AUR]] repository.
+
{{AUR|Guarddog}} requires {{Pkg|kdelibs3}} and is available in the [[AUR]] repository.
  
To have the firewall settings applied at bootup you must run ''/etc/rc.firewall'' from inside ''/etc/rc.local'' or something similar.
+
To have the firewall settings applied at boot-up you must run {{ic|/etc/rc.firewall}} from inside {{ic|/etc/rc.local}} or something similar.
  
===Gufw===
+
===Uncomplicated Firewall (ufw) Frontends===
[http://gufw.tuxfamily.org/index.html Gufw] is an easy to use Ubuntu / Linux firewall, powered by [[Firewalls#ufw|ufw]].  
+
[[Uncomplicated_Firewall#Gufw|Gufw]], a GTK-based front-end to {{Pkg|ufw}} which happens to be a CLI front-end to iptables (gufw->ufw->iptables), is super easy and super simple to use.
 +
{{Note|Gufw is perhaps the simplest replacement for tcp_wrappers, which was [https://www.archlinux.org/news/dropping-tcp_wrappers-support/ discontinued recently]}}
 +
[[Uncomplicated_Firewall#kcm-ufw|kcm-ufw]] is a KDE alternative to Gufw.
  
Gufw is an easy, intuitive, way to manage your Linux firewall. It supports common tasks such as allowing or blocking pre-configured, common p2p, or individual ports port(s), and many others! Gufw is powered by ufw , runs on Ubuntu, and anywhere else Python, GTK, and Ufw are available.  
+
See [[Uncomplicated_Firewall#GUI_frontends|Uncomplicated Firewall]] for more info.
  
 
===KMyFirewall===
 
===KMyFirewall===
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Firewall editing capabilities are simple enough to use to be suitable for beginners, but also allow for sophisticated tweaking of the firewall settings.
 
Firewall editing capabilities are simple enough to use to be suitable for beginners, but also allow for sophisticated tweaking of the firewall settings.
  
KMyFirewall requires kdelibs3 and is available in [[AUR]].
+
{{AUR|KMyFirewall}} requires {{Pkg|kdelibs3}} and is available in the [[Arch User Repository|AUR]].
  
 
==Firewall Builder==
 
==Firewall Builder==
 
[http://www.fwbuilder.org/ Firewall Builder] is "a GUI firewall configuration and management tool that supports iptables (netfilter), ipfilter, pf, ipfw, Cisco PIX (FWSM, ASA) and Cisco routers extended access lists. [...] The program runs on Linux, FreeBSD, OpenBSD, Windows and Mac OS X and can manage both local and remote firewalls." Source: http://www.fwbuilder.org/
 
[http://www.fwbuilder.org/ Firewall Builder] is "a GUI firewall configuration and management tool that supports iptables (netfilter), ipfilter, pf, ipfw, Cisco PIX (FWSM, ASA) and Cisco routers extended access lists. [...] The program runs on Linux, FreeBSD, OpenBSD, Windows and Mac OS X and can manage both local and remote firewalls." Source: http://www.fwbuilder.org/
  
{{Codeline|fwbuilder}} is available in the {{Codeline|extra}} repository.
+
{{Pkg|fwbuilder}} is available in the [[Official Repositories|official repositories]].
 +
 
 +
==Other==
 +
* {{App|[[Wikipedia:EtherApe|EtherApe]]|A graphical network monitor for various OSI layers and protocols.|http://etherape.sourceforge.net/|{{Pkg|etherape}}}}
 +
* {{App|[[Fail2ban]]|Bans IPs after too many failed authentification attempts against common daemons.|http://www.fail2ban.org/|{{Pkg|fail2ban}}}}
 +
 
 +
==See Also==
 +
Debian Wiki's list of Firewalls:
 +
http://wiki.debian.org/Firewalls

Revision as of 11:36, 3 January 2013


Tango-edit-clear.pngThis article or section needs language, wiki syntax or style improvements.Tango-edit-clear.png

Reason: convert to Template:App (Discuss in Talk:Firewalls#)

A firewall is a system designed to prevent unauthorized access to or from a private network (which could be just one machine). Firewalls can be implemented in only hardware or software, or a combination of both. Firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which examines each message and allows, proxys, or denies the traffic based on specified security criteria.

The firewalls listed in this article are overwhelmingly based on the iptables program. Consider configuring the iptables process yourself according to its wiki page (listed below) to keep to the The Arch Way.

There are many posts on the forums about different firewall apps and scripts so here they all are condensed into one page - please add your comments about each firewall, especially ease of use and a security check at Shields Up.

Note: Checks at Shields Up are only a valid measure of your router should you have one in the LAN. To accurately evaluate a software firewall, one needs to directly connect the box to the cable modem.

Firewall Guides & Tutorials

  • Uncomplicated Firewall, the wiki page for the simple iptables frontend, ufw, provides a nice tutorial for a basic configuration.
  • Router Setup Guide. A tutorial for turning a computer into an internet gateway/router. It focuses on security and configuring your gateway to have as few insecure holes to the internet as possible.

External Firewall Tutorials

  • http://tldp.org/HOWTO/Masquerading-Simple-HOWTO/IP Masq is a form of Network Address Translation or NAT that allows internally networked computers that do not have one or more registered Internet IP addresses to have the ability to communicate to the Internet via your Linux boxes single Internet IP address.

iptables front-ends

iptables

  • Iptables — A powerful firewall built into the Linux kernel that is part of the Netfilter project. Most firewalls, as described in this section below, are usually just front-ends.
http://www.netfilter.org/projects/iptables/index.html || iptables

Also see the man pages: (man iptables) – http://unixhelp.ed.ac.uk/CGI/man-cgi?iptables+8

Arno's Firewall

Arno's IPTABLES Firewall Script is a secure firewall for both single and multi-homed machines.

The script:

  • EASY to configure and highly customizable
  • daemon script included
  • a filter script that makes your firewall log more readable

Supports:

  • NAT and SNAT
  • port forwarding
  • ADSL ethernet modems with both static and dynamically assigned IPs
  • MAC address filtering
  • stealth port scan detection
  • DMZ and DMZ-2-LAN forwarding
  • protection against SYN/ICMP flooding
  • extensive user definable logging with rate limiting to prevent log flooding
  • all IP protocols and VPNs such as IPsec
  • plugin support to add extra features.

ferm

ferm (which stands for "For Easy Rule Making") is a tool to maintain complex firewalls, without having the trouble to rewrite the complex rules over and over again. ferm allows the entire firewall rule set to be stored in a separate file, and to be loaded with one command. The firewall configuration resembles structured programming-like language, which can contain levels and lists.

Firehol

FireHOL is a language to express firewalling rules, not just a script that produces some kind of a firewall. It makes building even sophisticated firewalls easy - the way you want it. The result is actually iptables rules.

firehol is available in the official repositories.

Firetable

Firetable is an iptables-based firewall with "human readable" syntax.

firetableAUR is available in the AUR.

Shorewall

The Shoreline Firewall, more commonly known as "Shorewall", is high-level tool for configuring Netfilter. You describe your firewall/gateway requirements using entries in a set of configuration files. Shorewall reads those configuration files and with the help of the iptables utility, Shorewall configures Netfilter to match your requirements. Shorewall can be used on a dedicated firewall system, a multi-function gateway/router/server or on a standalone GNU/Linux system. Shorewall does not use Netfilter's ipchains compatibility mode and can thus take advantage of Netfilter's connection state tracking capabilities.

shorewall is available in the official repositories.

ufw

ufw (uncomplicated firewall) is a simple front-end for iptables and is available in the official repositories.

See Uncomplicated Firewall for more information.

Vuurmuur

Vuurmuur Vuurmuur is a powerful firewall manager built on top of iptables. It has a simple and easy to learn configuration that allows both simple and complex configurations. The configuration can be fully configured through an ncurses GUI, which allows secure remote administration through SSH or on the console. Vuurmuur supports traffic shaping, has powerful monitoring features, which allow the administrator to look at the logs, connections and bandwidth usage in realtime.

VuurmuurAUR is available in the AUR.

iptables GUIs

Firestarter

Firestarter is a good GUI for iptables writen on GTK2, it has the ability to use both white and black lists for regulating traffic, it is very simple and easy to use, with good documentation available on their website.

FirestarterAUR has GNOME dependencies and is available in the AUR.

Guarddog

Guarddog is a really easy to use GUI for configuring iptables. After setting up a basic desktop configuration it passes all Shields Up tests perfectly.

GuarddogAUR requires kdelibs3 and is available in the AUR repository.

To have the firewall settings applied at boot-up you must run /etc/rc.firewall from inside /etc/rc.local or something similar.

Uncomplicated Firewall (ufw) Frontends

Gufw, a GTK-based front-end to ufw which happens to be a CLI front-end to iptables (gufw->ufw->iptables), is super easy and super simple to use.

Note: Gufw is perhaps the simplest replacement for tcp_wrappers, which was discontinued recently

kcm-ufw is a KDE alternative to Gufw.

See Uncomplicated Firewall for more info.

KMyFirewall

KMyFirewall is KDE3 GUI for iptables.

Firewall editing capabilities are simple enough to use to be suitable for beginners, but also allow for sophisticated tweaking of the firewall settings.

KMyFirewallAUR requires kdelibs3 and is available in the AUR.

Firewall Builder

Firewall Builder is "a GUI firewall configuration and management tool that supports iptables (netfilter), ipfilter, pf, ipfw, Cisco PIX (FWSM, ASA) and Cisco routers extended access lists. [...] The program runs on Linux, FreeBSD, OpenBSD, Windows and Mac OS X and can manage both local and remote firewalls." Source: http://www.fwbuilder.org/

fwbuilder is available in the official repositories.

Other

  • EtherApe — A graphical network monitor for various OSI layers and protocols.
http://etherape.sourceforge.net/ || etherape
  • Fail2ban — Bans IPs after too many failed authentification attempts against common daemons.
http://www.fail2ban.org/ || fail2ban

See Also

Debian Wiki's list of Firewalls: http://wiki.debian.org/Firewalls