seen on the Cirrus Forum
by Michael Thornburgh (February 1, 2017)
according to our server hosting provider, some of the Cirrus (codename) servers were hit with a DDoS attack, reported to us at 2017-02-01 18:15 UTC (Feb 1 2017 10:15am US Pacific time). the hosting provider blocked the servers being attacked. this was one of the two redirectors (load balancers) and one of the servers in the pool of P2P servers. the redundant redirector and other P2P servers in the pool were not affected and service continued.
as of 2017-02-02 19:16 UTC (Feb 2 2017 11:16am US Pacific time) our hosting provider reported that the attack was over and the blocks were lifted. Cirrus is back to full redundancy and capacity.