Security Expert needed for Centos server [iptables, tcpdump, Anti-DDOS]

Hello. I need a expert in iptables and security anti DDOS to improve the security in a Centos server that are attacked with flood attacks. I have several .pcap files recorded with TCPDump where can see the packets of the DDOS attack. I know that this attack are impossible to stop but i want advice about how to solve or deal this problem if with iptables or another method and mitigate the attacks and do not affect the service. I attach several capture samples of the packets of DDOS. Regards.