Ciao Enrico81, questo è il mio script per il firewall,
ancora più banale e semplice del tuo, ma per i miei attuali
scopi lo ritengo sufficiente.
codice:
#!/bin/bash
#
# /etc/firewall/wall
#
# My little personal firewall.
#

#############
# Variables #
#############
LO="lo"

#############################
# Loading modules and other #
#############################
echo "0" > /proc/sys/net/ipv4/ip_forward
echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_all
echo "1" > /proc/sys/net/ipv4/icmp_echo_ignore_broadcasts

#############################
# Initializing the firewall #
#############################
iptables -t filter -F
iptables -t filter -X
iptables -t filter -Z
iptables -t nat -F
iptables -t nat -X
iptables -t nat -Z

##############################
# Setting the default policy #
##############################
iptables -t filter -P INPUT DROP
iptables -t filter -P OUTPUT DROP
iptables -t filter -P FORWARD DROP

##################
# Defining rules #
##################
iptables -t filter -A INPUT -i $LO -j ACCEPT
iptables -t filter -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -t filter -A INPUT -m state --state INVALID -j LOG --log-prefix "INPUT(INVALID)->DROP: "
iptables -t filter -A OUTPUT -j ACCEPT
Riesco a connettermi a tutti i siti ftp.
Ho fatto scansioni delle porte online ed è risultata
una buona protezione della macchina. Adesso che sono
sotto router, vedo se spostare il firewall li' sopra.

Ciao.