List of well-known firewall technology for Linux systems

[kiran]

Firewall is a system which enforces access control policy between two networks. Many firewalls emphasize on blocking traffic
while some emphasize on permitting traffic. Firewall is not about only technical implementation of tool, but it's also strategy to be implemented for internet-reachable resources.



There are several types of firewall techniques, some of them are often used in combination.

Packet filter : This type of firewall looks at each packet entering or leaving the network and accepts or rejects it based on user-defined rules. Packet filtering is fairly effective and transparent to users, but it is difficult to configure. Packet Filtering uses the following factors to see if traffic has to be allowed or denied :

- Source and Destination IP address
- Protocol Type.
- Source Port and Destination Port.

Application gateway : Here security mechanisms are applied in application level. This is very effective, but can impose a performance degradation. Eg. FTP and Telnet servers.

Circuit-level gateway : Circuit-level gateways examine just TCP and UDP sessions. security rules are applied when connection is established. Once the connection has been made, packets can flow between the hosts without further checking.

Proxy Server : Proxy relays between two networks, effectively hides the true network source and destication addresses. It also typically caches Web pages.

Stateful Inspection : Tracks the transaction to ensure that inbound packets were requested by the user. Generally can examine multiple layers of the protocol stack, including the data, if required, so blocking can be made at any layer or depth.



There are various freely ( Open Source ) and commercial ( licensed ) firewall packages available in the internet world. Below is the list of well-known firewall technology used on Linux systems. Some of them are provided as module/addon/package in operating system, web hosting control panels or embedded in hardware device.

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iptables netfilter/iptables project homepage - The netfilter.org project

SmoothWall Express Open Source Firewall Project

m0n0wall ( Monowall ) m0n0wall

IPCop IPCop

pfSense pfSense Open Source Firewall Distribution - Home

Linux LiveCD Router Linux LiveCD Router Firewall Balancer Software Appliance

Sentry Firewall CD-ROM Sentry Firewall CD -- Firewall/IDS Node on a CD-ROM

UFW – Uncomplicated Firewall UFW (Uncomplicated firewall) For Ubuntu Hardy|Ubuntu Geek

OpenBSD and PF PF: The OpenBSD Packet Filter

Susefirewall SuSE Firewall

Firestarter Firestarter

Zorp GPL Gateway technology | Zorp

Turtle Turtle Firewall Home Page

LutelWall Linux Firewall - LutelWall

floppyfw floppyfw

Guarddog Guarddog

Endian Endian - *Unified Threat Management, Firewall Appliance, UTM Appliance, Hotspot, Antispam, Antivirus, VPN, OpenVPN, Open Source*

Firehol FireHOL, a Linux iptables packet filtering firewall builder for humans...

Devil-Linux Devil Linux - Home

ClarkConnect ClarkConnect becomes ClearOS - ClearSDN services and ClearCARE support available - Linux Small Business Server SBS

Shorewall Shoreline Firewall

Firewall Builder. Firewall Builder 4.0

Trustix Firewall Free Firewall Software Firewall Hardware VPN

Drawbridge Drawbridge

Cobia.stillsecure.com Cobia Unified Network Platform | Cobia

CensorNet Internet filtering software by the web filter experts Citrix ready | CensorNet

ClearOS ClearOS | Overview | Software

Gibraltar Gibraltar Firewall - UTM Security Gateways - Home

Mandrakesoft's integrated network security solution
Security Multi Network Firewall: Mandrakesoft |TechDirect

RedWall redWall Firewall

Securepoint Securepoint UTM 10 Security Appliances: Firewall, VPN Server, Virus scanner, Content Filter, Intrusion Detection and Prevention, network, Antivirus, Antispam, Roadwarrior, IPSec

CheckPoint FireWall Check Point - Security Appliances, Security Gateways, Security Management, Endpoint Security, and Software Blades

Cisco ASA/PIX Network Firewall - Main Page - Cisco Systems

Astaro Firewall

Plesk Firewall Module What's New in Plesk 7.5 Reloaded

CSF ConfigServer Security & Firewall

APF (Advanced Policy Firewall) Projects | R-fx Networks

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References and sources : wikipedia.org, company portals.

[Happyness]

Wow, that is a good number of firewalls to choose from. Is it possible to have two or three firewalls for better protection? Is this is possible then which programs are compatible with each other?

[Nevada832]

Thats a really good question. I'm interested in the answer too. I've always heard the firewalls can conflict, but I know a few people who run multiple firewalls. Maybe its an advanced user thing?

[kiran]

Originally Posted by Happyness

Wow, that is a good number of firewalls to choose from. Is it possible to have two or three firewalls for better protection? Is this is possible then which programs are compatible with each other?

Originally Posted by Nevada832

Thats a really good question. I'm interested in the answer too. I've always heard the firewalls can conflict, but I know a few people who run multiple firewalls. Maybe its an advanced user thing?

Originally Posted by Nevada832

is it ever appropriate to have multiple firewalls on a server? Perhaps an inherent must, or it can cause a dangerous conflict?

I'm not much experienced with multiple firewall configuration but after reading some technical articles and as per suppliers recommendation, One should make experiment, do test configuration and then apply experience.

Running compatible and properly configured 2 software firewalls provide proper defense against network traffic but it may also lead intermittent connection problems,decrease the effectiveness of the firewall. Some security expert suggest hardware firewall+software firewall as it provide in depth solution for attacks and prevent heavy network traffic. some of above firewall technologies are on iptables base so running such 2-3 simultaneously can conflict with each other and is recommended to disable one. Few are scripts/front-end for iptables which works altogether.

A firewall is only as good as its ruleset, no matter which known firewall you use.
I hope this explains

[calista]

This is very interesting to know so you can run more than one fire wall on one server or multiple servers but when they are iptables base is where you get the conflict. Is that right?