Overhead seems to be way down on the latest build, awesome! I've got maybe a 10% overhead now - back to where I was before uTP Can you elaborate a bit more ? what should we see as the result/effect those changes ? In regards to SYN with TCP, it usually refers to a synchronize sequence number. They're mostly ever only used to initiate a handshake with ACK/SYN (which I believe if memory serves me right, is short for acknowledge, sign - in reference to receiving an order and signing for it). Most DDoS attacks are done by flooding a connection with SYN packets, as they cause a lot of overhead, causing the machine to stop, process for longer than normal, and reply. They would be hugely useless on existing connections, especially UDP ones. Read up on TCP and it's SYN flag on Wiki: http://en.wikipedia.org/wiki/Transmission_Control_Protocol