How to break the connection from the IP from which DDoSyat?

Question

iptables

Hello everyone, the game server was DDoSed, well, as I understand it, not a botnet, but just a couple of flooders.
netstat -atnp | grep ESTA
Returns:
tcp 0 0 1**.80.47.170:27015 85.217.8.201:60769 ESTABLISHED 5089 /
srcds_linux
**. 80.47.170: 27015 85.217.8.79:60808 Established 5089 / SRCDS_Linux TCP
0 0 1 **. 80.47.170: 27015 158.64.175.211:60615 Established 5089 / SRCDS_Linux TCP
0 0 1 * 80.47.170: 27015 95.255.166.197:60923 ESTABLISHED 5089/srcds_linux
tcp 0 0 1**.80.47.170:27015 45.148.21.33:60929 ESTABLISHED 5089/srcds_linux
tcp 0 0 1**.80.47.170:22 5.15.142.89:61087 ESTABLISHED 15615/3
tcp 0 0 1**.80.47.170:27015 95.255.166.197:60922 ESTABLISHED 5089/srcds_linux 01.408
tcp .170: 27015 158.64.175.211:60 / srcds_linux TCP
0 0 1 **. 80.47.170: 27015 85.217.8.79:60810 Established 5089 / SRCDS_Linux TCP
0 0 1 * 80.47.170: 27015 45.148.21.33: 60933 ESTABLISHED 5089 / SRCDS_LINUX TCP
0 64 1 **. 80.47.170: 22 5.15.142.89:60428 Established 14459/1 TCP
0 0 1 * 80.47.170: 27015 158.64.175.211:60616 Established 5089 / SRCDS_Linux
tcp 0 0 1**.80.47.170:27015 5.59.142.89:61353 ESTABLISHED 5089
/
srcds_linux .170: 27015 95.255.166.197:60927 Established 5089 / SRCDS_Linux TCP
0 0 1 **. 80.47.170: 27015 5.59.142.89:8126 Established 5089 / SRCDS_Linux TCP
0 0 1 **. 80.47.170: 27015 85.217.8.79: 60805 ESTABLISHED 5089/srcds_linux I dropped them
all through iptables, but they still remained in netstat, although they do not harm anymore, can they be finally removed from there?

Answer 1

1) fail2ban (which is more profitable)
2) Ban by hand in iptables.

Answer 2

if DROP are prescribed after
then only new connections will drop,
you need to drop at the very beginning of the chain