[toast0]

I used to run the servers for a popular website. It was common to get DDoSed targeting our servers (or more frequently, just a single one out of the group) for exactly 90 seconds (plus or minus a few systems that had poor ntp synchronization). Whether or not that took my servers down, the attack would stop.

To my knowledge, we never got any communication from the people behind the attack, seemed like people just kicking the tires on DDoS as a service. Ocassionally, we'd get a longer interval, sometimes 60 minutes.