Iptables to allow ESTABLISHED,RELATED Connections
# iptables -A INPUT -m state –state ESTABLISHED,RELATED -j ACCEPT
# iptables -A OUTPUT -m state –state ESTABLISHED,RELATED -j ACCEPT
Iptables to allow yum OUTPUT on port 80
# iptables -A OUTPUT -p tcp -m tcp -m state –state NEW –dport 80 -j ACCEPT