Firetable
Firetable is an
IPtables firewall script for Linux. It has no graphical interface, all the configuration is done via configurationfiles. This makes Firetable ideal for servers. In the configurationfiles, you can write 'normal' sentences, for example:
set ntp_server ntp.isp.com
accept incoming tcp to server:{22, 25}
accept incoming udp from $ntp_server to domain:123
dnat tcp to server:80 -> webserver.lan
forward tcp to webserver.lan:80
This is of course much easier than the iptables commandline options.