What is iptables? iptables is the building block of a framework inside the Linux kernel. This framework enables packet filtering, network address translation (NAT), network port translation (NPT), and other packet mangling. iptables is a generic table structure for the definition of rulesets. Each rule with an IP table consists of a number of classifiers (iptables matches) and one connection action (iptable target). What can I do with iptables? build internet firewalls based on stateless and stateful packet filtering use NAT and masquerading for sharing internet access use NAT to implement transparent proxies do further packet manipulation (mangling) like altering the bits of the IP header
Nessus supports the following types of security audits: credentialed and un-credentialed port scanning network based vulnerability scanning credentialed based patch audits for Windows and most Unix platforms credentialed configuration auditing of most Windows and Unix platforms robust and comprehensive credentialed security testing of 3rd party applications such as iTunes, JAVA, Skype and Firefox custom and embedded web application vulnerability testing SQL database configuration auditing software enumeration on Unix and Windows testing anti-virus installs for out-of date signatures and configuration errors