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OSF - Passive OS Fingerprinting For IPtables

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Passive OS fingerprinting netfilter module allows to passively detect remote OS and perform various netfilter actions based on that knowledge. This module compares some data (WS, MSS, options and it's order, ttl, df and others) from packets with SYN bit set with dynamically loaded OS fingerprints. Starting from 2008_07_01 version OSF works only with Xtables, so you have to upgrade to recent kernels (and ename xtables support) and iptables (tested with 1.4.1.1). Also note, that Debian (starting from Lenny) has serious problems with iptables-dev package, which does not contain needed headers, so better install iptables from sources. Have you ever hear about a netfilter module that does passive OS fingerprinting? If you are interested in learning more about this check out this article.

Firewalk - Firewall Ruleset Testing Tool

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Firewalk is an active reconnaissance network security tool that attempts to determine what layer 4 protocols a given IP forwarding device will pass. Firewalk works by sending out TCP or UDP packets with a TTL one greater than the targeted gateway. If the gateway allows the traffic, it will forward the packets to the next hop where they will expire and elicit an ICMP_TIME_EXCEEDED message. If the gateway hostdoes not allow the traffic, it will likely drop the packets on the floor and we will see no response. Do you need to test your firewall? This article look at the firewall rulset testing tool called Firwalk. Test it how and let us know what you think?