For establishing outgoing active and passive FTP connection you can apply the following rules:
iptables -A INPUT -p tcp --sport 21 -m state --state ESTABLISHED -j ACCEPT
iptables -A INPUT -p tcp --sport 20 -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -p tcp --sport 1024: --dport 1024: -m state --state ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp --dport 21 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp --dport 20 -m state --state ESTABLISHED -j ACCEPT
iptables -A OUTPUT -p tcp --sport 1024: --dport 1024: -m state --state ESTABLISHED,RELATED,NEW -j ACCEPT
21: for default FTP port, if you don't use this change the port number20: to establish FTP connectionIt also allows the random ports >=1024 for related connections.
Comments