100% of us knows Ddos ,but have u ever faced Reflective Ddos attacks?

'I heared the attacker used some compromised servers(aka zombies) and constantly send's a large number of garbage packets with spoofed ip's and attacks a target,and also in return the target web-server also attacks(!?) via responding to the spoofed ip's,In this case what can we do to stop this attack?

even if the firewall admins started to block ip's,it leads to serious disaster right?

because if suppose the attacker uses the spoofed ip's starting from 1.1.1.1-254.254.254.254 means ,will it take take down the target server even tough it is having firewall protection?

Also if they started to ban ip's,they have to ban the entire internet right ?!!

Also i want to know,does any body here faced such massive reflective Ddos attacks?

Also indirectly the target web-server also attacking via responding to the spoofed ip's

Also how can we secure our-self against such massive sophisticated Ddos?