Like proxx said, still depends on what kind of attack. A UDP flood or SYN flood(any type of flood that does not require or use an established connection) will be 10GBit/s no matter what you do at your end. In this case you will have to contact the hosting provider and ask them to block it at a higher level so that the traffic never reaches your server.
However, many flood types are only effective because of poorly written services that will just accept tons and tons of gibberish data without severing the connection. In this case, just add the IP address of the flooder to iptables or if on windows, whatever firewall policy you are using.
