Open and Closed Source Firewalls

You can find a wide variety of firewalls available on the market today. Some are open source, such as Linuxs IPTables, OpenBSDs pf
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Open and Closed Source FirewallsOpen and Closed Source FirewallsYou can find a wide variety of firewalls available on the market today. Some are opensource, such as Linuxs IPTables, OpenBSDs pf, and the Solaris IPF firewalls. Others areclosed source, such as the Cisco PIX and ASA firewall operating systems, JunipersScreenOS, and Check Points firewall software. Some even use an underlying opensource operating system and firewall code with closed source modifications. Thedifferences between these firewalls are most typically noticeable in the additionalcapabilities of the commercial firewalls.Most commercial firewalls today provide for tight integration of VPN capabilities forremote users as well as deep packet inspection within the firewall itself. Open sourcefirewalls tend to focus on the filtering capabilities in the firewall process rather than theintegration of the firewall with other applications (and typically leave such capabilities asVPN and intrusion detection to other software systems). This focus can lead tointegration issues between other applications and the firewall itself but does not representan insurmountable obstacle.New companies have emerged that have taken open source firewall code and havecleaned up the management and improved the firewall such that the product producedrivals many of the closed source commercial firewalls. The business model of thesecompanies is to offer a trimmed-down version of the product for free and charge for themore complete version or charge for the support, which many business customers willwant in addition to the actual firewall. A good example of this model is the Shorewallfirewall.