How to avoid becoming a part of a DDoS attack?

Considering the magnitude of the recent DDoS attack on Dyn, that almost brought down the internet, all sysadmins must take action to prevent their devices from taking part in future attacks.

from SweetTech http://feedproxy.google.com/~r/TalkTechToMe-All/~3/SjyZQ0u0R8Q/