iptables is the userspace command line program used to configure the Linux 2.4.x and 2.6.x IPv4 packet filtering ruleset. It is targeted towards system administrators.
Since Network Address Translation is also configured from the packet filter ruleset, iptables is used for this, too.
The iptables package also includes ip6tables. ip6tables is used for configuring the IPv6 packet filter.
Rules with comment
iptables -I INPUT .... -m comment --comment="some comment"
How to stop iptables log from flooding console?
-stop syslog -dmesg -n 1 -start syslog
can't initialize iptables table `filter': iptables who? (do you need to insmod?)
Couldn't load target `LOG':No such file or directory
Means kernel module not loaded
Log with label
-j LOG --log-prefix="FOO"