Discover Firewalls News

Adaptive Firewalls with iptables

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Up until now, we've looked at stateless and stateful firewalls. Remember, stateless firewalls only have the features of a given packet to use as criteria for whether that packet should be passed, blocked, or logged. With a stateful firewall, in addition to the fields in that packet, we also have access to the kernel's table of open connections to use in deciding the fate of this packet. There's a problem, though. Picture an attacker that has launched attacks against almost every port on our web server box for the past half hour. The firewall has successfully repelled all of them, but now the attacker turns her attentions to port 80. All of the hostile overflow attempts are let through unhindered. Why? Because the firewall ruleset allows all traffic to the web server through, and our firewall can't remember the fact that this IP address has been pounding all the other ports on the system.

Help's A Firewall Away

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Flash back to December 2002. Barely in his 20s, self-taught network engineer and help-desk staffer Joel Bomgaars is frustrated because firewalls prevent him from accessing PCs of users needing help. At his cubical at systems integrator Business Communications Inc., he has an epiphany: Instead of accessing the user's computer, have the user request help by going to a Web site. That would clear the firewall hurdles, because firewalls only block incoming messages. The idea worked, and Bomgaars was able to connect with a user within 10 seconds.

Free Tool for Netfilter Announced

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In an effort to support the open source community, Solsoft Inc., the leading provider of network security policy management software, today announced its Solsoft NetfilterOne, a graphical interface that will automate the design, deployment and documentation of security rules and policies as they pertain to a networked netfilter firewall.