This is not unusual in what is essentially 'shared' IP space within cloud providers. It's easy for spammers to fire up a $5 droplet, send out a ton of spam, an

This is not unusual in what is essentially 'shared' IP space within cloud providers. It's easy for spammers to fire up a $5 droplet, send out a ton of spam, and disappear. Rackspace similarly recommends against sending from their cloud IP ranges.