we have install csf firewall on our server to protect server from ddos and etc
after a 1 day i see that all port are block so i try to service iptables stop for solve this problem
also i have disable csf
it means when iptables and csf are stop.
server is up and all port are open
so i decide to remove iptables from server
also some UDP error show on console about firewall and after iptables remove. all this problem solve...!!!!