[Help] attack on my serveur

hi all , i'm new in this forum
i need I need help
i'm admin of metin2 server and since 2 day , this server is crashed by an unknown

i install PF in my server but ... attacks continues and CH1 on my server is OFF after 2/3 minutes...

i also change port "P2P" in my server


how can I protect my server ?

thank you in advance

up