iptables -F

iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT DROP

//output settings
iptables -A OUTPUT -o lo -j ACCEPT
iptables -A OUTPUT -o eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT

iptables -A OUTPUT -o eth0 -p tcp -m tcp --sport 1024:65535 --dport 53 -m state --state NEW,ESTABLISHED -j ACCEPT
iptables -A OUTPUT -o eth0 -p udp -m udp --sport 1024:65535 --dport 53 -m state --state NEW,ESTABLISHED -j ACCEPT

//input settings
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -m state --state RELATED,ESTABLISHED -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -m state --state NEW -m tcp --dport 80 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -m state --state NEW -m tcp --dport 443 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -m state --state NEW -m tcp --dport 25 -j ACCEPT
iptables -A INPUT -i eth0 -p tcp -m state --state NEW -m tcp --dport 10000 -j ACCEPT

//ssh settings
iptables -A INPUT -i eth0 -p tcp -m state --state NEW -m tcp --dport 1234 -j ACCEPT