There is no practical way to actually prevent Dos / DDoS attacks, because your server is connected to the internet. When you are connected to the internet, even with a simple local PC computer you are exposed to remote attacks. The only thing you can do is to mittigate its effects. When you are under ddos and trying to mitigate the attack, the server will not respond normally, it will get slower than usual, it can often appear down temporary while the attack is decreasing. On large-volume attacks your provider can even null-route the server IP address to avoid from overload their entire network. Can CSF firewall help me to stop only small / medium attacks? Why not large attacks? Beacuse of the way DDOS works. For very large and distributed attacks, you must use a dedicated firewall, or an specialized antiddos shield that works on network level inside the datacenter where you are hosted, or you can use 3rd party anti-ddos services like Cloudflare, Incapsula or Level3 AntiDDOS servi...
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