olemus
tulemüürivahend Linuxi tuumas
=
the basic API that the Linux kernel offers for applications that want to view and manipulate network packets

ülevaateid
https://home.regit.org/netfilter-en/netfilter/

http://www.shorewall.org/NetfilterOverview.html

https://en.wikipedia.org/wiki/Netfilter

https://ajedrezvasco.com/infor/Iptables%20basics.pdf

veebisait
http://www.netfilter.org/