[sespindola]

The risk reduction is negligible if someone is doing a portscan on your host. Connection attempts to non standard ports will eventually occur. The better solution is to use single packet authorization.[1]

1. http://cipherdyne.org/fwknop/

[Florin_Andrei]

Yeah. It depends on how persistent they are. Using DROP on all closed ports may discourage some attackers. Others may remain undeterred.