Attached is a screenshot from a network packet capture I did of the sense network traffic against my internal router interface. It shows the different DNS requests I logged in a 120sec capture sample.
I also have whitelisted the following URLs in my web filter:
*sense.com
app.datadoghq.com
monitordata.s3.amazonaws.com
s3.amazonaws.com
sentry.io
I don’t see anything malicious in hardcoded DNS servers as they are just using Cloudflare, Google, and OpenDNS. Its just something to be aware of for us more technical SmartHome people. I was able to get my monitor working by whitelisting the Cloudflare DNS server (1.1.1.1).
Hardcoding the DNS servers probably resolved issues with smaller ISP DNS and other global DNS propagation issues causing downtime or outages for some Sense customers.