It can block your IP address at the firewall level. It can't stop you DDoSing it with raw packets, but that's very unlikely to happen unintentionally, because T

It can block your IP address at the firewall level. It can't stop you DDoSing it with raw packets, but that's very unlikely to happen unintentionally, because TCP will wait for a SYN-ACK response for at least several seconds and possibly up to several minutes.