iptables

Secure mail

#!/bin/sh

# Vider les tables actuelles
iptables -t filter -F

# Vider les règles personnelles
iptables -t filter -X

# Interdire toute connexion entrante et sortante
iptables -t filter -P INPUT DROP
iptables -t filter -P FORWARD DROP
iptables -t filter -P OUTPUT DROP

# ---

# Ne pas casser les connexions etablies
iptables -A INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

# Autoriser loopback
iptables -t filter -A INPUT -i lo -j ACCEPT
iptables -t filter -A OUTPUT -o lo -j ACCEPT

# ICMP (Ping)
iptables -t filter -A INPUT -p icmp -j ACCEPT
iptables -t filter -A OUTPUT -p icmp -j ACCEPT

# ---

# SSH In
iptables -t filter -A INPUT -p tcp --dport 3232 -j ACCEPT

# SSH Out
iptables -t filter -A OUTPUT -p tcp --dport 3232 -j ACCEPT

# DNS In/Out
iptables -t filter -A OUTPUT -p tcp --dport 53 -j ACCEPT
iptables -t filter -A OUTPUT -p udp --dport 53 -j ACCEPT
iptables -t filter -A INPUT -p tcp --dport 53 -j ACCEPT
iptables -t filter -A INPUT -p udp --dport 53 -j ACCEPT

# NTP Out
iptables -t filter -A OUTPUT -p udp --dport 123 -j ACCEPT

# HTTP + HTTPS Out
iptables -t filter -A OUTPUT -p tcp --dport 80 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 7071 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 443 -j ACCEPT

# HTTP + HTTPS In
iptables -t filter -A INPUT -p tcp --dport 80 -j ACCEPT
iptables -t filter -A INPUT -p tcp --dport 7071 -j ACCEPT
iptables -t filter -A INPUT -p tcp --dport 443 -j ACCEPT
iptables -t filter -A INPUT -p tcp --dport 8443 -j ACCEPT

# FTP Out
iptables -t filter -A OUTPUT -p tcp --dport 20:21 -j ACCEPT

# FTP In
modprobe ip_conntrack_ftp # ligne facultative avec les serveurs OVH
iptables -t filter -A INPUT -p tcp --dport 20:21 -j ACCEPT
iptables -t filter -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

# Mail SMTP:25
iptables -t filter -A INPUT -p tcp --dport 25 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 25 -j ACCEPT

# Mail SMTP:443
iptables -t filter -A INPUT -p tcp --dport 443 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 443 -j ACCEPT

# Mail SMTP:465
iptables -t filter -A INPUT -p tcp --dport 465 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 465 -j ACCEPT

# Mail SMTP:587
iptables -t filter -A INPUT -p tcp --dport 587 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 587 -j ACCEPT

# Mail POP3:110
iptables -t filter -A INPUT -p tcp --dport 110 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 110 -j ACCEPT

# Mail IMAP:143
iptables -t filter -A INPUT -p tcp --dport 143 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 143 -j ACCEPT

# Mail IMAP:993
iptables -t filter -A INPUT -p tcp --dport 993 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 993 -j ACCEPT

# Mail POP3S:995
iptables -t filter -A INPUT -p tcp --dport 995 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 995 -j ACCEPT

# Mail POP3S:9071
iptables -t filter -A INPUT -p tcp --dport 9071 -j ACCEPT
iptables -t filter -A OUTPUT -p tcp --dport 9071 -j ACCEPT

# Monit
iptables -t filter -A INPUT -p tcp --dport 8888 -j ACCEPT