Back in March, Shodan started a new service called Shodan Monitor(1). What this service does is notify you of ports that are open on the network you specify. When you initially setup your network, you put in your CIDR to monitor and then select notification triggers where you will get emails for any of these categories that show up on the specified network. In the notification emails, you get a link to be able to whitelist systems. I’m finding that the uncommon ports to be chatty for large networks, and tend to whitelist many of these.
Article Link: https://isc.sans.edu/diary/rss/24956