The ZARP server has been getting attacked for some time now (approx 6-9 hours) and we can't judge when this will be solved.
As I've explained in many similar threads; a DDoS is packets sent to a targeted IP address. These packets will continue to send until the server host manually blocks the attacking IP (if they have their IP displayed) or until the server has taken all the packets (depending on how big the attack is).
However; we do hope that this will stop soon!
EDIT; the attack isn't very strong either, it seems like someone is just DoSing it using their computer and a kiddy program. The packets being sent are very little. They aren't actually taking the server down, they can only just about send enough packets to send the server to a connection timeout but the server is still online.