Documentation: ============== The various netfilter and iptables HOWTOS can be found at: http://www.netfilter.org/documentation/ Bug Reports: ============ There's a bit of confusion and a lot of bug reports regarding iptables missing extension support. Basically, any given extension has kernel code and a complimentary user-space module to configure it. Without the kernel support, you get errors like this: ## example from http://www.securityfocus.com/infocus/1723 # iptables -A INPUT -p tcp -m tcp --dport 135 -j TARPIT iptables: No chain/target/match by that name In that example, the TARPIT extension is not available in the kernel. Without the user-space support, you get errors like this: # iptables -A INPUT -p tcp --dport 80 -j FOO iptables v1.4.0: Couldn't load target `FOO':/lib/iptables/libipt_FOO.so: cannot open shared object file: No such file or directory Try `iptables -h' or 'iptables --help' for more information. In that example, the user-space iptables extension FOO does not exist. The iptables package may have user-space support for extensions that may not be enabled in your kernel. That's a kernel issue. If possible, your kernel maintainer can add support. Reporting a bug on iptables will not help much there. The same goes for any netfilter kernel problems. Conversely, the iptables package may lack user-space support for kernel extensions that were added to your kernel. All or most stock extensions are already included with iptables.Bug reports for missing stock iptables user-space extensions are quite appropriate. Requests to add third party extensions and scripts to iptables are pretty much rejected wholesale for now. Some of the extensions (user-space + kernel code) are available from the netfilter ftp site and various third party locations. Your mileage may vary on adding any of those extensions.